Lift assembly systems and methods

ABSTRACT

A lift system comprises a drum that rotates about an axis, an elongate member that winds around the drum when the drum rotates in a first direction and that unwinds from the drum when the drum rotates in a second direction, a drive mechanism operable to rotate the drum, and a braking mechanism adapted to inhibit rotation of the drum. The braking mechanism includes a brake disk rotatable with the drum, a movable brake pad, and a ramp that guides movement of the movable brake pad. A method of operating the lift system comprises rotating the drum in a first direction to wind the elongate member onto the drum, rotating the drum in a second direction to unwind the elongate member from the drum, and moving the brake shoe along the ramp to thereby cause the movable brake pad to be compressed against the brake disk.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/340,277, filed Nov. 1, 2016, now U.S. Pat. No. 10,328,358, which is acontinuation of U.S. patent application Ser. No. 14/295,454, filed Jun.4, 2014, now U.S. Pat. No. 9,493,328, which is a continuation of U.S.patent application Ser. No. 14/136,611, filed Dec. 20, 2013, now U.S.Pat. No. 9,309,094, which is a continuation of U.S. patent applicationSer. No. 13/656,995, filed Oct. 22, 2012, now U.S. Pat. No. 8,613,428,which is a continuation of U.S. patent application Ser. No. 12/268,097filed Nov. 10, 2008, now U.S. Pat. No. 8,317,159, all of which claimpriority to U.S. Provisional Patent Application No. 60/986,499, filedNov. 8, 2007, U.S. Provisional Patent Application No. 61/023,562, filedJan. 25, 2008, and U.S. Provisional Patent Application No. 61/029,060,filed Feb. 15, 2008, all of the applications listed above are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to lift assembly systems and methods.Embodiments of the present invention may be useful for raising andlowering a load in theatrical and staging environments.

BACKGROUND OF THE INVENTION

Performance venues such as theaters, arenas, concert halls, auditoriums,schools, clubs, convention centers, and television studios can employbattens or trusses to suspend, elevate, and/or lower lighting, scenery,draperies, and other equipment that can be moved relative to a stage orfloor. Such battens can include pipe or joined pipe sections that form adesired length of the batten. Battens can be 50 feet or more in length.To support heavy loads or suspension points are that spaced apart, forexample, 15-30 feet apart, the battens may be fabricated in variousconfigurations, such as ladder, triangular, or box truss configurations.A number of elevating or hoisting systems are available for supporting,raising, and lowering battens and/or articles used in such venues.

Battens can be counterweighted in order to reduce the effective weightof the battens and any associated loads. As a result, the powernecessary to raise and lower battens can be reduced. However,conventional counterweight systems can represent a significant cost,with respect to both equipment required and time involved to installsuch equipment.

Some conventional elevating or hoisting systems can employ a winch toraise and/or lower battens and other articles. Such winches can behand-operated, motorized, and/or electrically powered. Otherconventional elevating or hoisting systems can utilize a hydraulic orpneumatic device to raise and/or lower battens.

Conventional elevating or hoisting systems can include a locking deviceand an overload limiting device. In a sandbag counterweight system, forexample, the locking device may be merely a rope tied off to astage-mounted pin rail. The overload limit can be regulated by the sizeof the sandbag. In such a rigging design, however, a number ofadditional bags can be added to the set of rope lines, and therebyexceed the safe limit of suspension ropes and defeat theoverload-limiting feature.

Elevating or hoisting systems that utilize winches can employ a lockingmechanism, such as a ratchet lock mechanism. When such winches areheavily loaded, the locking capacity of the ratchet lock, or otherlocking mechanism, can be overcome, resulting in the suspended loadbeing dangerously dropped. As a result, conventional lift systems canhave less than effective safety mechanisms.

In addition, conventional lift systems may be configured such that apulley, or loft block, mechanism is attached directly to an overheadbuilding support. As a result, an undesired amount of horizontal stresscan be placed on the overhead building supports to which the system andassociated load are attached.

Ropes or cables utilized to raise and/or lower a batten or other loadmay be wound about and unwound from a drum connected to a lift systemmotor. In conventional lift systems, the cables may rub unevenly againstadjacent cables as they are being wound about and unwound from the drum.Such uneven rubbing can cause friction that may increase the rate atwhich the cables, drum, and other components need to be serviced and/orreplaced. In addition, such friction can cause increased noise that maybe undesirable in certain performance environments.

Some conventional drums can have a size and/or coil cables about thedrums such that a large space is needed in which to locate the drum inor about the lift system. In “yo-yo” type drums and “pile” type drums,cables coil about the drum vertically on top of themselves. For example,in a “pile” type drum, after the cable has wound completely across theface of the drum, it is forced up to a second layer at a flange on theside of the drum. The cable then winds back across the drum in theopposite direction. In order to advance across the drum, the cable mustcross over two cable “notches” of the previous coil. Such “cross-over”subjects a cable to abrasion, crushing, and pinching as it is pushedover the two cable notches across the crown of the first cable layer.Such stress can cause erratic motion of the cables as they are wound uponto the drum and/or unwound from the drum. Such vertically stackedcoils of cables in conventional drums contribute to the need forincreased torque to wind and unwind cables on those drums.

Conventional lift systems can include a cable management system in whichelectrical wires in a cable are stacked in layers back and forth on topof each other. Such cable management systems risk pinching and/orbinding of the cable (and wires).

Thus, there is a need for a lift assembly drum that can wind and unwindcables in a smooth and controlled manner so as to minimize friction andnoise. There is a need for a lift assembly drum that can occupy arelatively small space. There is a need for a lift assembly drum thathas a decreased need for torque and is thus more energy-efficient. Thereis a need for a lift assembly system that includes a cable managementsystem that avoids unnecessary pinching or binding of electrical and/orother wires or cables as a load is raised and lowered.

SUMMARY

The present invention provides a lift system configured to lift anarticle. The lift system comprises a drum that rotates about an axis, anelongate member that winds around the drum when the drum rotates aboutthe axis in a first direction to raise the article and that unwinds fromthe drum when the drum rotates about the axis in a second direction tolower the article, a drive mechanism operable to rotate the drum aboutthe axis, and a braking mechanism adapted to inhibit rotation of thedrum. The braking mechanism includes a brake disk rotatable with thedrum, a movable brake pad (e.g., including a brake shoe), and a rampthat guides movement of the movable brake pad relative to the brakedisk. The braking mechanism can further include a fixed brake padpositioned adjacent the brake disk in opposing relation to the movablebrake pad. Preferably, rotation of the drum in the first directioncauses the movable brake pad to move away from the brake disk androtation of the drum in the second direction causes the movable brakepad to move toward the brake disk.

In one embodiment, the lift system further comprises a brake releasemechanism adapted to move the movable brake pad away from the brakedisk. For example, the brake release mechanism can include a pivotablebrake release arm that is capable of moving the movable brake pad awayfrom the brake disk. Preferably, the drive mechanism includes a motormounted for tilting, and the brake release mechanism is actuated bytilting of the motor.

The present invention also provides a method of operating a lift systemconfigured to lift an article. The lift system includes a drum, anelongate member wound around the drum, and a braking mechanism having abrake disk rotatable with the drum, a movable brake pad, a brake shoeattached to the movable brake pad, and a ramp that guides movement ofthe movable brake pad. The method comprises rotating the drum in a firstdirection to wind the elongate member onto the drum and lift thearticle, rotating the drum in a second direction to unwind the elongatemember from the drum and lower the article, and moving the brake shoealong the ramp to thereby cause the movable brake pad to be compressedagainst the brake disk to thereby substantially inhibit rotation of thedrum. Moving the brake shoe can cause the movable brake pad to movetoward a fixed brake pad positioned adjacent the brake disk in opposingrelation to the movable brake pad.

In one embodiment, rotating the drum in the first direction causes themovable brake pad to move away from the brake disk. Preferably, rotatingthe drum in the second direction includes moving the movable brake padaway from the brake disk in order to inhibit braking of the drum. Forexample, in a system wherein the drive mechanism includes a motor,moving the movable brake pad can include tilting the motor.

Features of lift assembly systems and methods may be accomplishedsingularly, or in combination, in one or more of the embodiments of thepresent invention. As will be realized by those of skill in the art,many different embodiments of lift assembly systems and methods arepossible. Additional uses, advantages, and features of aspects of thepresent invention are set forth in the illustrative embodimentsdiscussed in the detailed description herein and will become moreapparent to those skilled in the art upon examination of the following.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a lift assembly system in an embodiment of thepresent invention.

FIG. 2 is a view of a lift assembly system showing a drive mechanism anda partially cut-away view of a portion of a compression tube and thecomponents inside the tube in an embodiment of the present invention.

FIG. 3 is a close-up view of the drive mechanism shown in the liftassembly system in FIG. 2.

FIG. 4 is another close-up view of the drive mechanism shown in the liftassembly system in FIG. 2.

FIG. 5 is a perspective view of the head block end of a lift assemblysystem having the front half of the compression tube removed to show theinternal components in an embodiment of the present invention.

FIG. 6 is a perspective view of a drive mechanism, or power head, of alift assembly system showing a hybrid progressive drum in an embodimentof the present invention.

FIG. 7 is a perspective view of a hybrid drum having a constant diameterportion and a gradually increasing diameter portion useful in a powerhead in an embodiment of the present invention.

FIG. 8 is a diagrammatic, cross-sectional view of the drum in the liftassembly power head shown in the embodiment in FIG. 6, showing cableswound about the same diameter portion and the increasing diameterportion of the drum in a nested fashion.

FIG. 9 is a view of the drum in the lift assembly power head shown inthe embodiment in FIG. 6, opened along the axis of the drum andflattened to show the channels and the same diameter portion and theincreasing diameter portion of the drum.

FIG. 10 is a diagrammatic, perspective view of the drum in the liftassembly power head shown in the embodiment in FIG. 6, opened along theaxis of the drum and flattened, showing cables wound about the drum in anested fashion.

FIG. 11 is a diagrammatic, cross-sectional view of another embodiment ofa lift assembly drum, showing cables wound about the same diameterportion and the increasing diameter portion of the drum in a nestedfashion.

FIG. 12 is a perspective view of a cable management system, showing atray attached to a compression tube and first and second rollers forguiding an electrical wire containment cable into and out of the tray,in an embodiment of the present invention.

FIG. 13 is a view of a low profile distribution cable management systemhaving a tray attached to the top of a batten in an embodiment of a liftassembly of the present invention.

FIG. 14 is a view of a compression tube, power head, and particular loadconfiguration in an embodiment of a lift assembly of the presentinvention.

FIG. 15 is a view of a portion of a compression tube showing upwardextensions in an embodiment of a lift assembly of the present invention.

FIG. 16 is a view of a “sandwich” style compression tube splicing clampfor splicing together two abutting ends of tube portions in anembodiment of a lift assembly of the present invention.

FIG. 17 is a view of a plurality of beam clamp tube receivers attachedto an overhead support structure in an embodiment of the presentinvention.

FIG. 18 is a view of a compression tube in position to be inserted intoa beam clamp tube receiver in an embodiment of a lift assembly of thepresent invention.

FIG. 19 is a view of a compression tube attached to two overhead supportstructures, or beams, showing that the tube can be attached to beams atany location along the length of the tube and that loft blocks can bepositioned at any of an infinite number of locations along the length ofthe tube in an embodiment of a lift assembly of the present invention.

FIG. 20 is a view of a compression tube positioned within a beam clamptube receiver assembly, illustrating that the tube can easily slidelongitudinally within the beam clamp tube receiver assembly in anembodiment of a lift assembly system of the present invention.

FIG. 21 is a view of a self-locking block useful in an embodiment of alift assembly system of the present invention.

FIG. 22 is a view of a power head attached to a compression tube andloft blocks loaded in the tube in an embodiment of the presentinvention.

FIG. 23 is a view of a progressively sloped drum in an embodiment of alift assembly system of the present invention.

FIG. 24 is a view of a pair of low and high limit miter-geared limitswitches useful in an embodiment of a lift assembly of the presentinvention.

FIG. 25 is a view of a cable minder and a slack line detector in anembodiment of a lift assembly system of the present invention.

FIG. 26 is a view of a low profile, horizontally oriented cable adjusterin an embodiment of a lift assembly of the present invention.

FIG. 27 is a view of the low profile cable adjuster shown in FIG. 26, inwhich the wire cable is shown movably attached to a loft block.

FIG. 28 is a view of the low profile cable adjuster shown in FIG. 26,showing the cable adjuster assembly attached to a pair of battenattachment arms.

FIG. 29 is a view of another embodiment of a low profile, horizontallyoriented cable adjuster having a 90-degree cable guide block and a180-degree cable guide block for guiding the wire cable from the loftblock in a horizontal direction.

FIG. 30 is a view of a overspeed braking mechanism having the brake padhousing partially removed to show the brake pads and brake shoe insidethe brake pad housing in an embodiment of the present invention.

FIG. 31 is a view of the overspeed braking mechanism shown in FIG. 30,having the brake shoe removed to show the ramp.

FIG. 32 is a view of a fleet pivot arm pivotably attached to a tube inan embodiment of the present invention.

FIG. 33 is a view of a pull-type load sensor inside a drive mechanismhousing having a portion of the housing removed to show the load sensor,slide rails, and slide pate in an embodiment of the present invention.

FIG. 34 is a view of a cable management system in a tray on top of acompression tube in an embodiment of the present invention.

FIG. 35 is a view of components of a cable management system attached toa batten in an embodiment of the present invention.

FIG. 36 is a view of components of a cable management system attached toon one end of a batten in an embodiment of the present invention.

FIG. 37 is a view of components of a cable management system attached tothe opposite end of the batten shown in FIG. 36.

DETAILED DESCRIPTION

For the purposes of this application, unless otherwise indicated, allnumbers expressing quantities, conditions, and so forth used in thespecification are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the specification are approximationsthat can vary depending upon the desired properties sought to beobtained by the embodiments described herein. At the very least, eachnumerical parameter should at least be construed in light of the numberof reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the described embodiments are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements. Moreover, all ranges disclosedherein are to be understood to encompass any and all sub-ranges subsumedtherein. For example, a stated range of “1 to 10” should be consideredto include any and all sub-ranges between (and inclusive of) the minimumvalue of 1 and the maximum value of 10—that is, all sub-ranges beginningwith a minimum value of 1 or more, for example, 1 to 6.1, and endingwith a maximum value of 10 or less, for example, 5.5 to 10.

As used in this specification, the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, the term “a loft block” is intended to mean a singleloft block or more than one loft block.

Some embodiments of a lift assembly system 10 and method of the presentinvention can include a compression tube 11, a drum 24, an elongatemember, or cable 31, a drive mechanism 22, a head block 38, and a loftblock 32. The tube 11 can be a substantially rectangular tube having anopening in a bottom 15 along at least a portion of the length 16 of thetube 11. The tube 11 can be connectable to an overhead structure 57. Thedrum 24 can be located external to the tube 11 and adapted to wind andunwind the elongate member 31 to raise and lower an article 21 attachedto the elongate member 31. The drive mechanism 22 can be structurallyconnected to one end of the tube 11 externally. The drive mechanism 22can include a motor 27 rotatingly connected to the drum 24, such thatthe elongate member 31 extends along a first generally horizontal pathfrom the drum 24 to the tube 11. The head block 38 can be fixedlyconnected to an opposite end of the tube 11 and located to redirect theelongate member 31 from the first generally horizontal path to a secondgenerally horizontal path back toward the drive mechanism 22. The loftblock 32 can be connected to the tube 11 internally, spaced from thehead block 38, and located to redirect the elongate member 31 from thesecond generally horizontal path to a generally vertical path throughthe bottom 15 opening in the tube 11 to the attached article 21.

Some embodiments of such a lift assembly system 10 can include aplurality of the loft blocks 32. Each loft block 32 can be positionableand securable in place at an infinite number of locations along thelength 16 of the tube 11. In some embodiments, the lift assembly system10 can include a braking mechanism 36 connected to the elongate member31 and movable within the tube 11. Certain embodiments of the liftassembly system 10 can include a plurality of the tube 11 modulesarranged in an end-to-end configuration.

Exemplary embodiments of aspects of such a lift assembly system 10 areshown in FIGS. 1-6. Such embodiments are described in co-pending,co-owned U.S. patent application Ser. No. 11/796,781, filed Apr. 30,2007, which is incorporated herein by reference in its entirety. Anillustrative embodiment of a lift assembly system 10 can include thecoiling apparatus, or drum 24, a first traction drive 25 operablyconnected to the drive mechanism 22, a second traction drive 26, thetube 11 containing one or more pulleys, for example, the head block 38and the loft blocks 32, and one or more elongate members 31, such ascables. The cables 31 can be attached to the drum 24 and configured totravel in a generally horizontal path from the drum 24 around the secondtraction drive 26 to and around the first traction drive 25 to the headblock 38 and the loft blocks 32 inside the tube 11. From the loft blocks32, the cables 31 can travel in a generally vertical path, that is,upward and downward between the loft blocks 32 and a surface below. Anarticle 21, or load, can be attached to the cables 31 such that when thecables 31 are moved in the generally vertical path, the attached article21 can be raised and/or lowered relative to the surface.

Such embodiments of the lift assembly system 10 may be useful forraising and/or lowering articles 21, such as theatrical stage equipment,relative to a stage floor. Theatrical stage equipment can includeequipment which is to be raised and/or lowered prior to and/or during aperformance, in order to provide a desired scene effect. This equipmentcan include, for example, various rigging sets such as curtains,borders, screens, scene displays, props, lighting fixtures, and otherequipment. The rigging sets, some of which can be generally coextensivein length with the opening of a theater stage, can have substantial massand weight. Some embodiments of the lift assembly system 10 may be usedfor raising and/or lowering articles 21 and loads other than theatricalstage equipment.

In certain instances, the articles 21 to be raised and lowered can bestage equipment supported by one or more battens. A “batten” cancomprise an elongated pipe, rod, or rigid strip of material. Each battencan be supported along its length by a plurality of flexible cables.Although the term “batten” is used in connection with theatrical andstaging environment, including scenery, staging, lighting and soundequipment, etc., the term can encompass any load connectable to anelongate member 31, such as a windable cable.

Some embodiments of the lift assembly system 10 can be utilized inconnection with buildings in various settings. The term “building” asused herein can encompass a structure or facility to which the liftassembly 10 is connected, such as, but not limited to, performancevenues, theaters, arenas, concert halls, auditoriums, schools, clubs,educational institutions, stages, convention centers, televisionstudios, showrooms, places of religious gathering, cruise ships, etc.

In some embodiments of the present invention, the lift assembly system10 can include the coiling apparatus, or drum 24, as shown in FIGS. 2-4.One end of the cables 31, can be securely attached to the drum 24. Thedrum 24 can include a series of channels 46 or contoured surface areasabout which the cables 31 can be coiled, or wound, and from which thecables 31 can be uncoiled, or unwound. In some embodiments, the drum 24can include a channel 46 or contoured surface area for each cable 31 tobe wound and unwound. For example, as shown in the particularembodiments in FIGS. 3 and 5, the drum 24 can include eightcable-receiving channels 46. Each channel 46 or contoured surface areacan be sized to retain a length of cable 31 sufficient to dispose thearticle 21 connected to the cable 31 between a fully lowered positionand a fully raised position. Alternatively, the drum 24 can have asmooth surface about which the cables 31 can be wound and from which thecables 31 can be unwound in a side-by-side manner.

The drum 24 may be rotatably connected to the tube 11 and operablyconnected to the motor driveshaft 28 with a linking element, such as abelt, chain, or other linking mechanism. As shown in FIG. 3, forexample, the drum 24 can be operably connected to the first tractiondrive 25 with a drum drive belt 34.

In some embodiments, the lift assembly system 10 may include one or moretraction drives 25, 26. The traction drives 25, 26 can be rotatable suchthat cables 31 can move about the rotating surfaces of the tractiondrives 25, 26. The traction drives 25, 26 can include a series ofchannels 46 or contoured surface areas, similar to the channels 46 orcontoured surface areas in the drum 24, about which the cables 31 cantravel. The traction drives 25, 26 can be referred to as “sheaves.” Asheave is defined for purposes herein as a wheel or disc with a groovedrim, especially one used as a pulley.

In some embodiments, the lift assembly system 10 can include a drivemechanism 22. The drive mechanism 22 may include a motor 27, forexample, an electric motor 27. The drive mechanism 22 may furtherinclude a set of gears (not shown), which may be housed in a gear box30, for transferring rotational motion of the motor 27 to the driveshaft 28 and in turn to the first traction drive 25. The drive mechanism22 can be housed in a drive mechanism housing 23, as shown in FIG. 1.The motor 27 can cause rotation of the first traction drive 25 about itsrotational axis. In embodiments in which the second traction drive 26and the drum 24 are operably linked to the first traction drive 25, themotor 27 and gears can likewise cause rotation of the second tractiondrive 26 and the drum 24. The gears (not shown) in the gear box 30 canrotate the drive shaft 28, and the traction drives 25, 26 and drum 24,in a winding (raising) rotation and an unwinding (lowering) rotation.

The first traction drive 25 and the drum 24 can be operably connectedwith the drum drive belt 34, as described. In some embodiments, thefirst traction drive 25 and the drum 24 can rotate at predeterminedrelative speeds, or rates.

In some embodiments, the drive mechanism 22 can include a tension clutch37, as shown in FIG. 3. The tension clutch 37 can allow the drum 24 torotate at a different speed relative to the rotational speed of thefirst traction drive 25 so as to accommodate the variable drum-cablecircumference related to the amount of cable 31 wound about the drum 24at particular times during winding and unwinding of the cables 31.

In some embodiments, the drive mechanism 22 can be located completelyexternal to the tube 11 containing the loft blocks 32. Some embodimentsof the lift assembly system 10 can be equipped with different sizes andcapacities of motors 27.

Some embodiments of the lift assembly system 10 can be constructed tocooperate with at least one elongate member 31, such as a cable, orother length of material, connected at one end to the drum 24 and at theother end to the article 21 or load to be moved. In some embodiments,the number of cables 31 can be at as many as eight or more cables 31. Asused herein, “cable” is defined as a steel cable, steel tape (forexample, a one inch wide steel band), wire, metal, natural or syntheticrope, or other any other generally inelastic windable material suitablefor raising and lowering a load.

A length of cable 31 can be disposed about the drum 24 sufficient towind about the first and second traction drives, 25, 26, respectively,to extend horizontally to the head block 38 and to the loft block 32around which it moves, and then downward to the point at which it isconnected to the article 21 or load. The cable 31 can have a lengthsufficient to fully lower a desired article 21 or load.

In another aspect, some embodiments of the lift assembly system 10 caninclude the compression tube 11 as shown in FIGS. 1, 2, 4, and 5. Thecompression tube 11 can comprise a length of substantially rigidmaterial that can be connected to an overhead building structure 57. Asshown in FIG. 2, the compression tube 11 can include a plurality of loftblocks 32, or pulleys, disposed at intervals along the inside length 16of the tube 11. Each loft block 32 can rotatingly engage one or morecables 31. The loft blocks 32 can re-direct the generally horizontalpath of the cables 31 from the drum 24 and traction drives 25, 26 to agenerally vertical path to the attached article(s) below the compressiontube 11.

Depending upon several factors, including, for example, the dimensionsand weight of the article 21 to be raised and/or lowered, the number ofloft blocks 32 utilized in an embodiment of the present invention canvary. In some embodiments, for example, the lift assembly system 10 caninclude eight loft blocks 32 and thus eight cable drop points, ascompared to some conventional lift assemblies which provide seven orfewer loft blocks 32. In this manner, the lift assembly system 10 canprovide greater support to the article 21 and greater flexibility as tolocations on the article 21 to which the cables 31 can be attached.

In certain embodiments, the compression tube 11 can include a means forengaging the loft blocks 32. For example, the means for engaging theloft blocks 32 can include a rail 44 extending outwardly into theinterior of the tube 11. Each of the loft block sliders 33 can have agroove 50 along its length adopted to slidingly engage the tube rail 44.Alternatively, the means for engaging the loft blocks 32 can include achannel in the length 16 of the opposing walls of the tube 11. Each ofthe loft block sliders 33 can have an arm extending outwardly from eachside of the loft block sliders 33 that can slidingly engage the channelsalong the tube 11. Once the loft block 32 is in a desired position alongthe length 16 of the tube 11, the locking mechanism 52 can be actuatedto secure the loft block 32 in that position.

The head block 38 can be located to redirect the elongate member 31, orcable, from a first generally horizontal path from the drive mechanism22 to a second generally horizontal path to the loft blocks 32 back inthe direction of the drive mechanism 22. The head block 38 can includechannels 46 for aligning and directing each of a plurality of the cables31. As shown in FIG. 5, certain embodiments of the head block 38 caninclude a bifurcated rotating surface such that the cables 31 can bespaced apart into two groups so as to provide a space in the centeralong the length 16 of the tube 11 for locating the loft blocks 32.

The compression tube 11 can include an opening in the bottom 15 of thetube 11 along at least a portion of the length 16 of the tube 11. Thecables 31 that are routed about the loft blocks 32 can be routeddownward through the opening for movement upward and downward to raiseand lower the attached article 21.

In some embodiments, for example, as shown in FIGS. 1 and 5, thecompression tube 11 can include a connecting mechanism disposed on thetop 14 of the tube 11 for connecting the tube 11 to an overheadstructure 57, such as a building support beam. The connecting mechanismcan comprise connector arms 17 that can be movable toward and away fromeach other. The connecting mechanism can include a tightening mechanism,such as a biasing mechanism, for releasably securing the connectingmechanism about the structure 57.

Some embodiments of the lift assembly system 10 can include a singleprimary compression tube 11 unit having a predetermined length. In otherembodiments, the lift assembly system 10 can include a primarycompression tube 11 unit and one or more extension units of thecompression tube 11. In such embodiments, the extension tube 11 unit(s)can include a desired number of loft blocks 32, and can be installedend-to-end with the primary tube 11 unit to provide a length ofcompression tube 11 having various desired lengths. In this arrangement,the lift assembly system 10 can include a single drive mechanism 22 atone end of the primary tube 11 unit. The cables 31 to be routed throughthe bottom 15 of the extension tube 11 unit can be routed from thesingle drive mechanism 22 on the drive end 18 of the primary tube 11through the opposite end of the primary tube 11, to the head block 38,if included, and to the loft blocks 32 in the extension tube 11. In thismanner, the lift assembly system 10 can include various lengths of thecompression tube 11 and various numbers of the loft blocks 32 forrouting a corresponding number of the cables 31 to the article 21 to bemoved. Alternatively, compression tubes 11 and/or extensions can bemanufactured in customized lengths.

In another aspect of the present invention, some embodiments of the liftassembly system 10 may include a braking mechanism 36. The brakingmechanism 36 can be an overspeed braking system. As shown in FIGS. 2 and3, the brake 36 can be a “load-side” overspeed brake. That is, the brake36 can be attached to a lift assembly 10 component other than the motor27. In this configuration, should the motor 27 and/or gears controllingspeed of cable movement fail, the lift assembly system 10 can provide abraking mechanism 36 separate from operation of the drive mechanism 23for preventing free fall of a load attached to the cables 31. In thismanner, the load-side brake 36 can provide redundancy relative to thepower-train components for controlling downward movement, for example,slowing or stopping, of a load attached to the cables 31.

FIG. 5 shows another illustrative embodiment of a lift assembly system.In some embodiments, the lift assembly system 10 can include asubstantially rectangular tube 11 having a front and a rear C-shapedportion connected together to form a front 12, rear 13, top 14, andbottom 15 of the tube 11. In FIG. 5, the top 14 and front 12 portions ofthe tube 11 have been removed to show the arrangement of componentsinside the tube 11. The C-shaped portions of the tube 11 can beconfigured such that when the portions are connected together, thebottom 15 edges of the front and rear portions 12, 13, respectively,remain spaced apart, thereby providing the opening in the bottom 15along at least a portion of the length 16 of the tube 11. The tube 11can be connectable to the overhead structure 57, such as a buildingsupport beam.

The lift system 10 can include the drum 24 positioned externally to thetube 11, as shown in FIGS. 2-5. The drum 24 can be adapted to wind andunwind one or more elongate members 31, such as cables, to raise andlower the article 21 attached to the elongate members 31. The liftsystem 10 can further include the drive mechanism 22, as shown in FIGS.2-5, structurally connected to the drive end 18 of the tube 11externally. The drive mechanism 22 can comprise the motor 27 rotatinglyconnected to the first traction drive 25 and operably connected to thedrum 24 and to the second traction drive 26. In such a configuration,the elongate member 31 can extend along a first generally horizontalpath from the drum 24 about the first and second traction drives 25, 26,respectively, to the tube 11.

The head block 38 can be fixedly connected to the head block end 20 ofthe tube 11 opposite the drive end 18. As shown in FIG. 5, the headblock 38 can rotate about a head block axle 42, which is supported oneither side of the head block 38 in a head block axle support 41. A headblock mount 40 can be attached to and extend from the axle support 41 oneach side of the head block 38. The head block mount 40 can be rotatedinto alignment with a surface of the tube 11 and be fastened to the tube11 so as to secure the head block 38 to the tube 11. The head block 38can be located to redirect the elongate member 31 from the firstgenerally horizontal path to a second generally horizontal path from thehead block 38 back toward the drive mechanism 22.

The loft block 32 can be spaced from the head block 38 and connected toan internal portion of the tube 11. The loft block 32 can be located toredirect the elongate member 31 from the second generally horizontalpath to a generally vertical path through the bottom opening in the tube11 to the attached article 21. In some embodiments, the lift system 10can include a plurality of the loft blocks 32. Each loft block 32 can bepositioned at an infinite number of locations on the continuum along thelength 16 of the tube 11.

The loft block 32 can further include the loft block slider 33 adaptedto position and/or reposition the loft block 32 at a desired locationalong the length 16 of the tube 11. The loft block slider 33 cancomprise a front slider arm 45 spaced apart from a rear slider arm 47,and a support bar 48 on each end of the loft block slider 33 connectingthe front and rear slider arms 45, 47, respectively. A loft block axle(not shown) can be supported on one end by the front slider arm 45 andon the opposite end by the rear slider arm 47. The loft block 32 can berotatingly attached about the loft block axle. Each of the front andrear loft block slider arms 45, 47, respectively, can include the groove50 along the length 16 of the slider arm 45, 47. The groove 50 an beadapted to slidingly engage a respective lower front rail or lower rearrail 44 along the length 16 of the tube 11. By sliding the loft blockslider groove 50 along the lower tube rails 44, the loft block 32 can bepositioned at a desired location along the length 16 of the tube 11.

The loft block slider 33 can further include a locking mechanism 52disposed on each of the front and rear slider arms 45.47, respectively,for locking the loft block 32 in a desired position along the length 16of the tube 11. In the embodiment shown in FIG. 5, the loft block sliderlocking mechanism 52 can include a tab 51 located on each end of thefront and rear slider arms 45, 47, respectively, and a biasing mechanismattached to each tab 51. When the tabs 51 are depressed, the biasingmechanism is released and the loft block slider 33 can be slid along thefront and rear tube rails 44. When the tabs 51 are released, the biasingmechanism is actuated so as to lock the loft block 32 onto the front andrear tube rails 44.

In some embodiments, the lift system 10 can include a tube supportslider 53, as shown in FIG. 5. The tube support slider 53 may bepositioned along the length 16 of the tube 11 to provide additionalfront-to-rear structural support to the tube 11. For example, each of aplurality of the tube support sliders 53 may be positioned in betweenlocations of the loft blocks 32. The tube support slider 53 can besimilar to the loft block slider 33 in design and operation. The tubesupport slider 53 can comprise the front slider arm 45 spaced apart fromthe rear slider arm 47, and the support bar 48 on each end of the tubesupport slider 53 connecting the front and rear slider arms 45, 47,respectively. Each of the front and rear tube support slider arms 45,47, respectively, can include the groove 50 along the length of theslider arms 45, 47. The groove 50 can be adapted to slidingly engage arespective upper front rail or upper rear rail 43 along the length 16 ofthe tube 11. By sliding the tube support slider groove 50 along theupper tube rails 43, the tube support slider 53 can be positioned at adesired location along the length 16 of the tube 11.

The tube support slider 53 can further include the locking mechanism 52disposed on each of the front and rear slider arms 45, 47, respectively,for locking the tube support slider 53 in a desired position along thelength 16 of the tube 11. The tube support slider locking mechanism 52can include the tab 51 located on each end of the front and rear sliderarms 45, 47, respectively, and a biasing mechanism attached to each tab51. When the tabs 51 are depressed, the biasing mechanism is releasedand the tube support slider 53 can be slid along the front and rear tuberails 44. When the tabs 51 are released, the biasing mechanism isactuated so as to lock the tube support slider 53 onto the front andrear tube rails 44.

In certain embodiments, the loft block sliders 33 and the tube supportsliders 53 can provide structural support to the compression tube 11 soas to help prevent the tube 11 from bowing outwardly in a perpendiculardirection relative to the length 16 of the tube 11. As horizontal stressis placed on the lift system 10 between the drive mechanism 22 and theloft blocks 32 by a load attached to the cables, the tube 11 may have atendency to bow outwardly from front 12 to back 13. Thus, the loft blocksliders 33 and the tube support sliders 53 can help prevent the tube 11from bowing outwardly in a perpendicular direction relative to thelength 16 of the tube 11.

As shown in the embodiment in FIG. 5, the lift assembly system 10 canfurther include a tube overhead connector 54, also known as a beam clamptube receiver 118, having a front connector sleeve 55 and rear connectorsleeve 56, also known as hooks 122. The beam clamp tube receiver 118 andhooks 122 are described later with reference to FIGS. 17-20.

As described herein, the lift assembly drive mechanism, or power head22, can include the motor 27. In some embodiments, the power head 22 canfurther include the gear box 30 attached to the motor 27. The driveshaft 28 can extend outwardly from the gear box 30 and/or motor 27. Thedrum 24 can be fixedly attached about the end of the drive shaft 28extending from the gear box 30 and/or motor 27 such that when the driveshaft 28 rotates, the drum 24 can be rotated in the same direction asthe drive shaft 28. The drive shaft 28 and drum 24 can be rotated inopposite directions, for example, forward and backward.

The drum 24 can have a particular shape capable of accommodating windingand unwinding of the cables 31 about the external surface of the drum24. In some embodiments of the lift assembly system 10, the drum 24 cancomprise a hybrid drum 58 having a funnel shape, as shown in FIGS. 6-11and 23. In some embodiments, at least a portion of the funnel-shaped, orfrusto-conical shaped, drum 58 can have a progressively increasingdiameter. As shown in the embodiment in FIG. 6, the drum 58 can beattached to the drive shaft 28 such that the more narrow portion, orapex 60, of the funnel, is attached to the drive shaft 28 at a pointdistal from the motor 27. In this configuration, the drum 58 cangradually increase in diameter along the width 62 of the drum 58 towardthe motor 27 to provide an increasing diameter portion 63 of the drum58. In other embodiments, the drum 58 can be attached to the drive shaft27 such that the apex 60 of the drum funnel is attached to the driveshaft 28 at a point proximal to the motor 27 (as shown in FIG. 23). Inthis configuration, the drum 58 can gradually increase in diameter alongthe width 62 of the drum 58 away from the motor 27.

The drum 58 can have various diameters and widths from the most narrowapex 60 of the drum 58 to the widest part, or base 61, of the drum 58.For example, a drum 58 suitable for accommodating five cables 31, eachcable 31 about ⅛ inch in diameter, can be about four inches wide. Such adrum 58 may be useful, for example, in a fixed speed lift assembly. Inan illustrative embodiment of a variable speed lift assembly, the drum58 may have eight channels 46 and eight cables 31, each cable 31 about3/16 inch in diameter and having a length sufficient to accommodate 65feet of travel. Such a drum 58 may be approximately 11 inches wide andhave a progressively increasing diameter from about four inches to about14 inches. The drum may have other larger diameters as needed. The drum58 can be made of a variety of materials suitable for supporting thecables 31 and a load, such as the article 21, attached to the cables 31.For example, the drum 58 can comprise steel, aluminum, and/or plastic.In certain applications, it may be preferable to have a drum 58 that isas light weight as possible. One lightweight embodiment of the drum 58of the present invention may be made from glass filled Nylatron. Such adrum embodiment may be injection molded.

In certain embodiments, the drum 58 can include a portion extending fromthe apex 60 a predetermined distance toward, for example, the motor 27(as shown in FIG. 6), having the same diameter before the drum 58 beginsto gradually increase in diameter. The same, or constant, diameter drumportion 64 can include grooves, or channels 46, in its external surfacein which cables 31 can be routed.

The drum 58 can be rotated in one direction so that cables 31 unwind, orpay out, from the external surface of the drum 58 and rotated in theopposite direction so that the cables 31 are wound about the drum. Whenthe drum 58 is rotated so as to wind cables 31 about the drum 58, afirst cable 65 can be wound in a first channel 68 adjacent the point ofthe drum 58 that begins to gradually increase in diameter. As shown inFIG. 6, the first cable 65 can be wound about the drum 58 such that thefirst loop, or coil 74, of the first cable 65 is wound about the drum 58in the first channel 68 about the same diameter portion 64 of the drum58. The first cable 65 can then be wound about the drum 58 in an angledchannel 73 along the external surface of the increasing diameter portion63 of the drum 58. As the first cable 65 is further wound about the drum58, the next, or second, coil 75 of the first cable 65 is adjacent thefirst coil 74 and located about the drum 58 at a point having a slightlyincreased diameter than the constant diameter portion 64 of the drum 58.Each subsequent coil of the first cable 65 can be wound adjacent thepreceding coil about gradually increasing diameters of the drum 58. Whenthe first cable 65 is completely wound about the drum 58, substantiallythe entire external surface of the drum 58 can be covered with adjacentcoils of the first cable 65. Such a drum 58 having a graduallyincreasing diameter can be referred to as a “progressive” drum 58, asthe cables 31 can be wound about a progressively larger diameter of thedrum 58. Because the drum 58 has a constant diameter portion 64 and aprogressively, or gradually, increasing diameter portion 63, the drum 58can be referred to as a “hybrid” drum 58.

The drum 58 can include a second channel 70 adjacent to the firstchannel 68 on the opposite side of the first channel 68 from theincreasing diameter portion 63 of the drum 58. As the drum 58 is rotatedso as to wind the cables 31 about the drum 58, a second cable 66 can bewound in the second channel 70 and about the coils of the first cable65. As shown in FIG. 7, the first coil 76 of the second cable 66 can bewound in the second channel 70 about the constant (smaller) diameterportion 64 of the drum 58. The second coil 77 of the second cable 66 canthen be wound about the same diameter portion 64 of the drum 58 in anotch 72 between the first coil 76 of the second cable 66 and the firstcoil 74 of the first cable 65. The third coil 78 of the second cable 66can then be wound about the drum 58 at a point having a slightlyincreased diameter between the first and second coils 74, 75,respectively, of the first cable 65. Each subsequent coil of the secondcable 66 can be wound adjacent the preceding coil and about graduallyincreasing diameters of the drum 58. In this manner, coils of the secondcable 66 can be wound about the drum 58 into the notches 72 betweenadjacent coils of the first cable 65 such that the second cable 66“nests” within the coils of the first cable 65. When the second cable 66is completely wound about the drum 58, all but the last few coils (forexample, the last two coils) of the first cable 65 can be covered withadjacent coils of the second cable 66.

As shown in FIGS. 8 and 11, each subsequent cable 31 adjacent apreceding cable 31 (which is more distal from the increasing diameterportion 63 of the drum 58) can be wound about the drum 58 in the samemanner. That is, a subsequent cable 31 can be wound first about the samediameter portion 64 of the drum 58 in a channel 46 for that cable 31 andin notches 72 between a coil of that cable 31 and a coil of theadjacent, already wound-up cable 31, and then about the drum 58 atpoints having gradually increasing diameters in notches 72 between acoil of that cable 31 and a coil of the adjacent cable 31. Eachsubsequent cable 31 can thus be wound about the drum 58 into the notches72 of the adjacent, already wound-up cable 31 such that each subsequentcable 31 “nests” within the coils of the adjacent, already wound-upcable 31. Generally, each of the cables 31 can be wound about the drum58 and unwound from the drum 58 substantially simultaneously.

In certain embodiments, the channels 46 in the same diameter portion 64of the drum 58 may be spaced from each other, and/or the diameters ofthe cables 31 relative to those spacings may be such, so that more thanone or two coils of a cable 31 may be wound about the same diameterportion 64 of the drum 58 before being wound about the increasingdiameter portion 63 of the drum 58. For example, as shown in FIGS. 7 and11, the first three coils 76, 77, 78, respectively, of the second cable66 can be wound about the same diameter portion 64 of the drum 58. Thespacing between the first and second channels 68, 70, respectively, andthe diameters of the cables relative to that spacing can allow the firstand second coils 76, 77 of the second cable 66 and the second and thirdcoils 77, 78, respectively, of the second cable 66 to “stack” adjacentto each other at substantially the angle of the increasing diameterportion 64 of the drum 58.

Embodiments of the present invention having a “nesting” feature ofadjacent cables 31 wound about the funnel-shaped drum 58 have theadvantage of winding about the drum 58 and unwinding from the drum 58 insuch a manner so as to avoid uneven rubbing against adjacent cables 31.The channels 46 in the surface of the drum 58 can also facilitate theeven movement of the cables 31 as they are wound about and unwound fromthe drum 58. As a result, the cables 31 can be wound and unwound withless friction and with less noise than manners in which cables 31 arewound and unwound in conventional lift or hoist systems. Decreasedfriction in such lift systems 10 can advantageously decreaserequirements for maintenance and prolong the effective life of the drum58, cables 31, and lift system 10. Decreased noise may be a benefit incertain performance environments in which minimal noise from movement ofa lift system may be desired.

In addition, such a “nesting” feature and the increasing diameter of theprogressive, funnel-shaped drum 58 allow the cables 31 to be wound aboutthe drum 58 in a smaller space. As a result, the width 62, and overallsize, of the drum 58 can be smaller than conventional drums, such as“yo-yo” type drums or “pile” type drums in which cables 31 coil aboutthe drum vertically on top of themselves. In a “yo yo” drum, designedfor light loads and infrequent duty cycles (such as lights that need tobe moved only periodically to change bulbs), coils of individual cables31 stack vertically on top of previous coils. In “pile” type drums,after the cable 31 has wound completely across the face of the drum, itis forced up to a second layer at a flange on the side of the drum. Thecable 31 then winds back across the drum in the opposite direction. Inorder to advance across the drum, the cable must cross horizontally overthe crown of the cable 31 in each previous coil. Such “cross-over”subjects the cable 31 to abrasion, crushing, and pinching as it ispushed across the cable crown of the first cable layer. Such stress cancause erratic motion of the cables 31 as they are wound up onto the drumand/or unwound from the drum.

Embodiments of the progressively increasing diameter hybrid drum 58 canthus provide the advantage of coiling cables 31 directly into anglednotches 72 without having to push a subsequent cable 31 over the crownof the previously coiled cable 31. In addition, embodiments of theprogressively increasing diameter hybrid drum 58 can minimize, orsignificantly reduce, the need for increased torque to wind and unwindcables 31 on conventional drums having vertically stacked coils ofcables 31. That is, a smaller and more lightweight drum 58, as providedin embodiments of the present invention, can advantageously decrease thetorque needed to move the drum 58 and cables 31, allowing a smallermotor 27 and gearbox 30 than in conventional lift systems. Smaller drumand power head 22 components may be less expensive than conventionalcomponents, and their decreased bulk can allow placement of the drum 58in alternative locations in or about the lift system 10. As an example,some conventional lift system power heads (motor, gearbox, and drum)that accommodate a maximum of seven cables 31 may weigh between 500 and850 pounds. In some embodiments of the present invention, the power head22 may accommodate eight cables 31, which may be required in manytheater applications, and weigh as little as 180 pounds. In someembodiments, the drum 58 can be oriented perpendicularly to the travelpath of the cables 31 (not shown). In this manner, no translating motionis required (as in conventional lift systems) to wind and unwind thecables 31 on the drum 58. As a result, less energy is required to movethe cables 31 relative to the drum 58.

The embodiments shown in FIGS. 6, 7, 8, and 10 illustrate the drum 58having five channels 46 and five cables 31. In other embodiments, thedrum 58 can include more or less than five channels 46 and cables 31,depending on the intended use of the lift system 10 of which the drum 58is a component. For example, one embodiment of the lift system 10 may beused as a fixed speed lift for movement of a bank of lights and that mayrequire a relatively smaller number of cables 31 and thus fewer channels46. Another embodiment of the lift system 10 may be used for variablespeed movement of, for example, theatrical sets, for which a relativelylarger number of cables 31 and channels 46 may be desired. As anexample, the embodiment in FIG. 11 illustrates the drum 58 having eightchannels 46 and cables 31. In certain embodiments, one or more cables 31in the lift system 10 can have more than one lift line attached to theend of the cable 31 for attaching to a plurality of points along thelength of a load, such as a batten, to be raised and lowered. Inparticular embodiments, one of the cables 31 can be attached to a cablemanagement system 100, such as a sheath of electrical wires, or lines,attached to lights on a batten, for moving the electrical lines up anddown with movement of the batten by the other cables 31.

In some embodiments, the end of the drum 58 at its smallest diameterapex 60 can include a flange 81 extending upward from the surface of thedrum 58. In some embodiments, the end of the drum 58 at its largestdiameter, or base 61, can include a flange 81 extending upward from thesurface of the drum 58. Such flanges 81 can serve to maintain the cables31 on the drum 58 during winding and unwinding. However, in certainembodiments, the cables 31 can be sufficiently maintained in thededicated channels 46 and/or supported in position by nesting onto eachother during winding without apex and/or base flanges 81.

In some embodiments, the power head 22 can be attached directly to thelift assembly structure, such as the compression tube 11. For example,the ends of the drive shaft 28 can extend outwardly from opposite sidesof the gear box 30, and each end of the drive shaft 28 can be rotatinglyattached to opposite sides of the compression tube 11. Alternatively, asshown in the embodiment in FIG. 6, the power head 22 may include twospaced-apart side plates 82. Each end of the drive shaft 28 can berotatingly attached to one of the side plates 82. One or more supportbars 83 can extend between the side plates 82. A support plate 84 canextend between the two side plates 82 a distance from the motor 27, gearbox 30, drum 58, support bars 83, and other power head components so asto at least partially enclose the power head 22 between the side plates82 and support plate 84. The support bar(s) 83 and support plate 84 canprovide structural support to the side plates 82. In this configuration,the side plates 82 can be attached to the compression tube 11 or otherassembly of head block(s) 38 and loft blocks 32 in the lift system 10.

The lift system power head 22 may include the braking mechanism 36. Forexample, as shown in the embodiment in FIG. 6, the braking mechanism 36can include a brake disk 85 operably connected to the portion of thedrive shaft 28 extending outward from the gear box 30 (or motor 27) onthe side of the gear box 30 opposite the drum 58. Alternatively, thebrake disk 85 can be connected to the drive shaft 28 adjacent the drum58. The braking mechanism 36 can be configured to help regulate movementof the drive shaft 28, drum 58, and cables 31 and thereby movement of aload attached to the cables 31. Such a braking mechanism 36 can becontrollable by mechanical and/or electronic means.

Some embodiments of the lift system 10 can include a cable guidemechanism. The cable guide mechanism can comprise a guide assembly 86for guiding movement of the cables 31 from the drum 58 to loft blocks 32as they are unwound from the drum 58 and from the loft blocks 32 to thedrum 58 as they are wound about the drum 58. As shown in FIG. 6, theguide assembly 86 can include a guide block 87 having one guide hole 88for each cable 31 to be wound and unwound from the drum 58. The guideassembly system 86 can further include a guide block travel support arm90. In some embodiments, the support arm 90 can be fixed to the supportplate 84. A portion of the support arm 90 can extend at the end of thesupport arm 90 substantially perpendicularly to the remainder of thesupport arm 90. The support arm 90 can include such an extension 91 onone or both ends of the support arm 90. A guide bar 92 can be fixed onone end to the support arm extension 91, and on its opposite end theguide bar 92 can be slidably attached to the guide block 87. The guideblock 87 can be slidably attached about the guide bar 92 such that theguide block 87 can move parallel to the drive shaft 28. In anotherembodiment, the guide block 87 can include a roller (not shown)comprising the same number of roller channels as the channels 46 on thedrum 58 and adapted so that one of each of the cables 31 can be guidedabout one of the roller channels to maintain the cables 31 in positionbetween the drum 58 and the loft blocks 32.

The guide assembly 86 can further include a pulley 93 rotatinglyattached to the adjacent side plate 82 or other structure a distancefrom the drum 58 and within the power head 22. The pulley 93 can beoperably attached to the drive shaft 28 with a linking mechanism 94, forexample, a belt or chain. In this manner, when the drive shaft 28rotates in one direction, the pulley 93 rotates in the same direction asthe drive shaft 28 and at a constant speed relative to the speed ofdrive shaft rotation. A pulley shaft 95 can extend outward from thepulley 93. A threaded rod 96 can be operably connected to the pulleyshaft 95, for example, with a rotating joint 97. The guide rod joint 97can be a “universal” type joint that allows the threaded rod 96 to berotated at an angle relative to the longitudinal axis of the pulleyshaft 95. The threaded rod 96 can be rotatingly attached on the endopposite the pulley 93 to the support arm extension 91. The guide block87 can include a threaded slot 98 that can be matingly engaged with thethreaded rod 96, for example, an ACME® rod.

In such a configuration, when the drive shaft 28 rotates in a directionso as to wind the cables 31 about the drum 58, the pulley 93 rotates inthe same direction as the drive shaft 28 and drum 58. The rotatingpulley 93 causes the threaded rod 96 to rotate in the same, windingdirection as, and with a constant speed relative to, the drive shaft 28,thereby causing the guide block 87 to ride upward along the threaded rod96 and the guide bar 92. In this way, the cables 31 being wound aboutthe drum 58 can be guided from the loft blocks 32 through the guideholes 88 in the guide block 87 along the width of the surface of thedrum 58 and parallel to the drive shaft 28. Likewise, when the driveshaft 28 rotates in the opposite direction so as to unwind the cables 31from the drum 58, the pulley 93 rotates in the same direction as, andwith a constant speed relative to, the drive shaft 28 and drum 58. Therotating pulley 93 causes the threaded rod 96 to rotate in the same,unwind direction as the drive shaft 28, thereby causing the guide block87 to ride downward along the threaded rod 96 and the guide bar 92. Inthis way, the cables 31 being unwound from the drum 58 can be guided tothe loft blocks 32 through the guide holes 88 in the guide block 87along substantially the same decreasing angle as the angle at which thecables 31 are paid out along the surface of the drum 58. As a result,the guide assembly 86 can help maintain the cables 31 at the same angle(the “fleet” angle) along the route of the cables 31 to and from theloft blocks 32 as the angle at which the cables 31 leave the surface ofthe drum 58 during unwinding and return to the drum 58 surface duringwinding.

Maintaining cable fleet angles in this manner can provide the benefit ofpreventing the cables 31 from unnecessarily rubbing against each other,thereby increasing efficiency of movement, decreasing “wear and tear” onthe cables 31 and other lift system components, and decreasing noise.The fleet angle of cables 31 from conventional drums, for example, a“yo-yo” type drum on which cables 31 stack vertically, must bemaintained within a narrow fleet angle tolerance, such as one andone-half degrees, in order to prevent the cables 31 from rubbing thesides of the drum and/or from falling off the lock block 32. Inembodiments of the present invention, maintaining such a precise fleetangle may not be as critical, since the cables 31 can be wound up in amore horizontal and angled fashion. In some embodiments, the fleet anglecan operate smoothly and effectively within a range of plus or minus oneand one-half degrees variation as the cables 31 travel between the drum58 and the loft blocks 32.

Certain embodiments of the lift assembly system 10 comprising the hybridprogressive drum 58 may operate effectively without the guide assembly86. However, in embodiments comprising such a guide assembly, or system86, additional safety may be provided by helping maintain the cables 31in position during winding and unwinding operations.

Some embodiments of the present invention can include a method forraising and lowering the article 21. Embodiments of components of thelift assembly system 10 described herein may be utilized in such amethod. Such a method can include, for example, providing a lift system10 comprising (a) the substantially rectangular tube 11 connectable tothe overhead structure 57, (b) the drive mechanism 22 connectedexternally on one end of the tube 11, (c) the drum 24 or the hybrid drum58 operably connected to the drive mechanism 22, and (d) the pluralityof loft blocks 32 connected to the tube 11 internally. A plurality ofthe cables 31, each attached on one end to the drum 24, 58, can berouted through a generally horizontal path of travel from the drum 24,58 to one of the loft blocks 32, and then through a generally verticalpath of travel downward from the loft block 32. An opposite end of eachcable 31 can be attached to the article 21. The cables 31 can then bewound about the drum 24, 58 to raise the article 21 and unwound from thedrum 24, 58 to lower the article 21.

In some embodiments of such a method, the drum can have a funnel-shape,as does the hybrid progressive drum 58, and can include the samediameter portion 64 and the increasing diameter portion 63, each portionhaving channels 46 in its surface for guiding the cables 31. When thedrum 58 is rotated so as to wind the cables 31 about the drum 58, thefirst cable 65 can be wound in the first channel 68 adjacent the pointof the drum 58 that begins to gradually increase in diameter. The firstcable 65 can be wound about the drum 58 such that the first coil 74 ofthe first cable 65 is wound about the drum 58 in the first channel 68about the same diameter portion 64 of the drum 58. The first cable 65can then be wound about the drum 58 in an angled channel 73 along theexternal surface of the increasing diameter portion 63 of the drum 58.Subsequent coils of the first cable 65 can be wound adjacent thepreceding coil and about gradually increasing diameters of the drum 58.In some embodiments, the surface of the drum 58 can be smooth.

In such a method, the drum 58 can include the second channel 70 adjacentto the first channel 68 on the opposite side of the first channel 68from the increasing diameter portion 63 of the drum 58. As the drum 58is rotated so as to wind the cables 31 about the drum 58, the secondcable 66 can be wound in the second channel 70 and about the coils ofthe first cable 65. The first coil 76 of the second cable 66 can bewound in the second channel 70 about the same diameter portion 64 of thedrum 58. The second coil 77 of the second cable 66 can then be woundabout the same diameter portion 64 of the drum 58 in the notch 72between the first coil 76 of the second cable 66 and the first coil 74of the first cable 65. The third coil 78 of the second cable 66 can thenbe wound about the drum 58 at a point having a slightly increaseddiameter between the first and second coils 74, 75, respectively, of thefirst cable 65. Each subsequent coil of the second cable 66 can be woundadjacent the preceding coil and about gradually increasing diameters ofthe drum 58. In this manner, coils 76, 77, 78, 80 of the second cable 66can be wound about the drum 58 into the notches 72 between adjacentcoils of the first cable 65 such that the second cable 66 “nests” withinthe coils 74, 75, 76 of the first cable 65. Subsequent adjacent cables31 can be wound about the drum 58 in a similar manner such that coils ofthose cables 31 “nest” in notches 72 of the adjacent, previouslywound-up cable 31.

In some embodiments of a method, the cables 31 can be guided by theguide assembly 86 as they are unwound from the drum 58 to loft blocks 32and as they are wound about the drum 32 from the loft blocks 32. Asshown in FIG. 6, the guide assembly 86 can include the guide block 87having one guide hole 88 for each cable 31 to be wound about and unwoundfrom the drum 58. The guide assembly system 86 can be operably connectedto the motor 27 so that the guide block 87 can move at the same rate asthe drum 58. The guide block 87 can be configured so as to move alongparallel to the drive shaft 28. In this way, the cables 31 being woundabout the drum 58 can be guided from the loft blocks 32 through theguide holes 88 in the guide block 87, or about a guide roller attachedto the guide block 87, along the width of the drum 58. As a result, theguide assembly 86 can help maintain the cables 31 at the same “fleet”angle along the route of the cables 31 to and from the loft blocks 32 asthe angle at which the cables 31 leave the surface of the drum 58 duringunwinding and return to the drum 58 surface during winding.

Some embodiments of the lift system 10 of the present invention caninclude a cable management system 100. The cable management system 100can include a mechanism for stacking wires, for example, electricalwires from lights, as they are being raised and lowered. In someembodiments of the lift system 10, electrical wires and/or other typesof wires can be contained in an outer sheath, which can be referred toas a wire containment cable 101, or wire cable. The wire containmentcable 101 may be about four inches wide, for example. The wires at theend of the wire containment cable 101 proximal to the batten or otherload can be connected to an output object, for example, electricaloutlets or lights, attached to the batten. The end of the wire cable 101opposite the batten can be connected to an input source, for example, apower source.

In conventional cable management systems, the wires, or wire cable, canfold back and forth periodically on themselves in a “scissoring” or“switchback” fashion, for example, every few feet. One risk of foldingwires back onto themselves repeatedly is that they can be undesirablypinched, and can become worn over time. Some embodiments of the cablemanagement system 100 according to the present invention include asystem for controlling movement of such electrical wires, and/or othercables, so as to avoid unnecessary pinching or binding.

In some conventional cable management systems, the electrical wire cableis collected in a tray positioned on top of a batten as the batten israised. Such a tray may be referred to as a “flip flop” tray, since aportion of the electrical wire cable can be “flipped” in one directionand then “flopped” back onto itself in the opposite direction. Adisadvantage of allowing such wire cables to collect in a stackedfashion on top of a batten, particularly on one end of the batten, isthat the collected cables can cause the batten to be top heavy, whichmay cause the batten to become unbalanced and undesirably alter theorientation of the batten and/or articles attached to the batten.

In some embodiments of the present invention, the cable managementsystem 100 can include a housing, or tray 102, attached to thecompression tube 11. The tray 102 can have dimensions suitable forcontaining the wire cable 101. As shown in the embodiment in FIG. 12,the tray 102 can be attached to the exterior of one side of thecompression tube 11. The tray 102 can extend along the entire length 16of the tube 11, or along a portion of the tube 11, for example, themajority of the length 16 of the tube 11. The cable management system100 can include rollers about which the wire containment cable 101 canbe guided into and positioned in the tray 102 and guided out of the tray102. A first roller 103 can be stationarily attached to one end of thetray 102. In certain embodiments, the first roller 103 can be attachedto the end of the tray 102 adjacent the power head 22 of the liftassembly 10. In certain embodiments, the first roller 103 can be gearedto correspond with the gearing of the power head motor 27 so that thefirst roller 103 rotates in the same direction and at the same speed asthe drum 58 connected to the motor 27. A second roller 104 can bemovably attached to the tray 102 such that the second roller 104 moves apredetermined distance along the length of the tray 102 as the batten israised and lowered.

The wire containment cable 101 can be connected to one of the load liftcables 31, such as the cables 31 described herein with reference toFIGS. 6-11, that wind about and unwind from the drum 58 in the liftsystem power head 22. The lift cable 31 to which the wire containmentcable 101 can be attached can be a wire cable lift cable 105. The wirecable lift cable 105 can be routed from the drum 58 to a wire cable liftcable loft block 106 near the end of the tube 11 opposite the power head22, around the loft block 106, and back in the opposite direction towardthe power head 22. The wire cable lift cable 105 can be attached at itsdistal end to the wire cable 101 and to the second roller 104. As aresult, the wire containment cable 101 can move in the same direction(vertically) and at the same rate as the lift cables 31 and the loadattached to the lift cables 31. As the lift cables 31 are wound onto thedrum 58, the second roller 104 moves toward the wire cable loft block106, and the wire cable lift cable 105 moves around the wire cable loftblock 106 and is likewise wound onto the drum 58 the same amount and atthe same rate as the lift cables 31 attached to the load, or article 21,are wound. As the lift cables 31 are unwound from the drum 58, the wirecable lift cable 105 is likewise unwound from the drum 58 and movesaround the wire cable loft block 106, allowing the second roller 104 tomove away from the wire cable loft block 106 and lower the wire cable101 the same amount and at the same rate as the lift cables 31 attachedto the load are lowered.

When the batten is in a lowered position, the wire containment cable 101can extend downward from the tray 102 around the first roller 103 to thebatten or load. As the load attached to the lift cables 31 is raised,the wire cable 101 can be routed from its substantially verticalposition, about the top of the first roller 103, and to a substantiallyhorizontal position in the tray 102. The wire cable 101 can be guidedabout the top of the second roller 104 such that, as the load is raised,the wire cable 101 is positioned so as to lie flat in the tray 102. Whenthe article 21 is fully raised to a position adjacent the tube 11, thewire containment cable 101 can be positioned flat in a single layeralong the length of the tray 102.

The wire containment cable 101 may be “single purchased,” defined as aone-to-one relationship of the horizontal movement to the verticalmovement of the wire cable 101. As the wire cable 101 moves a particulardistance 107 vertically while the lift cables 31 (and load) are beingmoved vertically, the wire cable 101 moves that same distance 108horizontally about and within the tray 102. In certain embodiments, thewire containment cable 101 can be “double purchased,” in that as thelift cables 31 and the wire containment cable 101 move a particularvertical distance 107 , the wire cable 101 can be moved about and withinthe tray 102 a horizontal distance 108, which is less than the verticaldistance 107. The horizontal distance 108 may be, for example, about onehalf the vertical distance 107. That is, as the wire cable 101 is movedupward while the load is being raised, the wire cable 101 may be doubledonto itself within the tray 102. As an example, if the wire cable 101 israised 60 feet vertically, the wire cable 101 may move in one directionhorizontally for 30 feet, for example, and then be folded back ontoitself by the second roller 104 into the tray 102 in the oppositedirection for 30 feet. In this way, the wire cable 101 can be foldedback onto itself once, allowing both layers of the wire cable 101 to lieflat along a substantial distance within the tray 102. In embodiments inwhich the wire containment cable 101 is “single purchased,” the wirelift cable 105 can be “single purchased.” In embodiments in which thewire containment cable 101 is “double purchased,” the wire lift cable105 can be “double purchased.”

FIG. 34 illustrates another embodiment of the cable management system100 in which the tray 102 is disposed on the compression tube 11. Asshown in FIGS. 15 and 34, the tray 102 can comprise the top 14 of thecompression tube 11 between upward extensions 116 along the length 16 ofthe tube 11. Such an embodiment of the cable management system 100 caninclude the wire cable loft block 106 attached to the end of the tube 11opposite the power head 22. In some embodiments, the wire cable loftblock 106 can comprise a pair of side-by-side pulleys. The cablemanagement system 100 can further include a truck 110 that can slidealong the length 16 of the top 14 of the tube 11, that is, along thelength 16 of the tray 102, along a guide rail 111. The guide rail 111can have a “T” shape, for example, as shown as the T-rail 120 in FIG.15, and the truck 110 can be configured to matingly slide along theT-rail 111. The truck 110 can include a pulley, or sheave, about whichthe cable 31 can move. A pulley 109 can be fixed in the tray 102 on thepower head end 18 of the lift assembly system 10.

The lift cable 31 can be one of the plurality of lift cables 31 attachedto the drum 58, and can be routed to the wire cable loft block 106 onthe end of the tray 102 opposite the power head 22. The cable 31 canthen be routed about a first pulley in the wire cable loft block 106back in the direction toward the power head 22 and be connected to thetruck 110 in the tray 102. The wire cable lift cable 105 can be attachedon one end to a fastener 99 adjacent the power head 22, routed about thepulley attached to the truck 110, to the pulley 109 fixed on the powerhead end 18 of the lift assembly system 10, about the pulley 109, to asecond pulley in the wire cable loft block 106, and about the wire cableloft block 106 into a substantially vertical downward direction.

When the drum 58 winds the lift cables 31 about the drum 58, the wirecable lift cable 105 and the attached truck 110 are pulled toward thewire cable loft block 106. This movement causes the truck 110 to pullthe cable 31 to raise the wire containment cable 101 attached to thelift cable 31. When the drum 58 unwinds the lift cables 31 from the drum58, the wire cable lift cable 105 and the attached truck 110 are allowedto move toward the pulley 109 near the power head 22. This movementallows the cable 31 to lower the wire containment cable 101 attached tothe lift cable 31.

FIGS. 35-37 illustrate embodiments of the cable management system 100having components attached to the batten, or article, 21. As shown inFIG. 35, one or more wire containment cables 101 can be attached on oneend to an electrical box input source 180 located near the compressiontube 11. FIG. 35 shows a compressed vertical view of the wirecontainment cables 101 that extend between the tube 11 and the article21. The wire containment cables 101 can be routed downward from one ormore of the electrical box input sources 180 in a substantially verticaldirection to the wire containment cable rollers 181 and about therollers 181 onto the top of the article 21. In some embodiments, onepair of the wire containment cables 101 can be positioned on top of theother pair on top of the batten article 21 when the article 21 israised.

FIG. 36 shows the wire cable lift cable 105 routed substantiallyvertically downward from the wire cable loft block 106 and about apulley 182 fixed to a batten attachment 143 on the end of the batten 21below the wire cable loft block 106. The wire cable lift cable 105 canthen be routed substantially horizontally toward the opposite end of thebatten 21 about the pulley 183 attached to a trolley 184. The trolley184 can ride on roller 186 along the top of the length of the batten 21.The trolley 184 can be at least partially enclosed by trolley walls 185.The top and front walls 185 of the trolley 184 are removed in FIG. 37 toshow the internal portions of the trolley 184. The wire cable lift cable105 can be routed from the pulley 183 back in the opposite direction toa point of attachment on the batten attachment arm 143 below the pulley182. In this manner, when the lift cables 31 are wound about the drum 58to raise the batten article 21, the wire cable lift cable 105 and thetrolley 184 are pulled toward the pulley 182. This movement causes thetrolley 184 to pull the wire containment cable 101 in position along thetop of the batten. When the lift cables 31 are unwound from the drum 58,the wire cable lift cable 105 and the attached trolley 184 are allowedto move away from pulley 182. This movement allows the wire cable liftcable 101 to be extended in a substantially vertical direction betweenthe tube 11 and the article 21.

In certain embodiments, the cable management system 100 can include twowire cable lift cables 105 that extend substantially vertically downwardfrom the tube 11 when the article 21 is lowered. In such embodiments,the wire cable lift cable 105 on one end of the article 21 can be pulledby a first trolley 184 toward the center of the article 21, therebypositioning a first wire containment cable 101 on the batten 21. Thefirst trolley 184 can have a cable attached to the first trolley 184routed about a pulley on the end of the batten article 21 nearest thefirst trolley 184 and back in the opposite direction to a second, slavetrolley 184 (not shown). A second wire cable lift cable 105 can extenddownward from the tube 11 to the second, slave trolley, about a pulleyon the trolley, and to an attachment point on the end of the batten 21opposite the first trolley 184. As the first trolley 184 is pulledtoward the center of the batten article 21, the second, slave trolleyand the second wire cable lift cable are likewise pulled toward thecenter of the batten 21, thereby positioning the second wire containmentcable 101 on the batten 21.

In certain embodiments of the cable management system 100 of the presentinvention, the tray 102 can be attached to the top of a batten or otherload to be raised and lowered. FIG. 13 is a view of the low profiledistribution cable management system 100 in which the tray 102 isattached to the top of the batten, or article 21, from which lights canbe attached. The low profile distribution cable management system 100can include the tray 102 comprising, for example, aluminum. In such anembodiment, the first roller 103 can be rotatingly fixed to the end ofthe tray 102 below the end of the tube 11 to which the power head 22 isattached. The flat electrical cable 101 may be connected to the powerhead 22 of the lift assembly 10, which may be located at near theceiling of a building. The flat wire containment cable 101 can move upand down with the batten, following a path that goes from the power head22 substantially vertically downward, around the first roller 103 at theend of the tray 102, then horizontally in the tray 102, and around themoveable second roller 103 that travels in the tray 102. The moveablesecond roller 104 in the tray 102 may be connected by one of the liftcables 31 to the same drum 58 as the other lift cables 31 used to raiseand lower the batten. In this way, the flat, electrical wire containmentcable 101 may be moved in synchronization with the batten to which it isattached. The wire containment cable 101 that moves with the secondroller 104 in the tray 102 may be attached to a truck 110 that can moveinternally along the length 16 of the tube 11 along a guiding T-shapedrail 111. The truck 110 may be connected to the wire cable lift cable105 that winds about the power head drum 58 with the other load liftcables 31 that raise and lower the batten. The truck 110 can slide alongthe T-rail 111 and can serve as an interface between the power head 22and the cable 105 running down to the tray 102 that is on the batten.The truck 110 may serve as a double- or triple-purchasing device toenable the flat electrical cable 101 to move at appropriate speedsand/or lengths in synchronization with the batten. In certainembodiments, the cable management system 100 can be primarily containedinside the compression tube 11. This can allow the entire lift assembly10 having cable management to be pre-rigged at the factory.

In such embodiments, the roller system (first and second rollers 103,104, respectively) can lay the wire containment cable 101 into the tray102 in a flatter arrangement than in conventional cable managementsystems. In addition, because the wire cable 101 can be positioned inthe tray 102 substantially from one end of the tube 11 to the other(when “single purchased”), or, alternatively, about half of the lengthof the tray 102 (when “double purchased”), the wire cable 101 does notstack as high as in conventional systems, where the wire cable 101 maystack on top of itself six to eight times or more. In this way, certainembodiments of the present invention can avoid the stacked height of thewire cable 101 on top of the batten as in conventional systems, therebyproviding a more stable and balanced positioning of the wire cable 101on the batten. Because in some embodiments of the present invention thewire cable 101 is stacked in such a flatter arrangement on top of thebatten, the batten and attached articles can travel a greater distance(that is, more closely to the overhead tube 11) than in conventionalsystems in which the wire cable 101 is stacked multiple times on itselfat the top of the batten.

Some embodiments of the present invention can include a method formanaging the wire containment cable 101 while raising and lowering thearticle 21. Some embodiments of such a method can include providing thetray 102 attached to the compression tube 11, for example, to theexterior of one side of the tube 11. The tray 102 can extend along theentire length 16 of the tube 11, or along a portion of the length 16 ofthe tube 11. The method can further include providing rollers 103, 104about which the wire containment cable 101 can be guided into and out ofthe tray 102. The first roller 103 can be rotatingly attached to one endof the tray 102. In certain embodiments, the first roller 103 can beattached to the end of the tray 102 adjacent the power head 22 of thelift assembly 10. The first roller 103 can be geared to correspond withthe gearing of the power head motor 27 so that the first roller 103rotates in the same direction and at the same speed as the drum 58connected to the motor 27. The second roller 104 can be movably attachedto the tray 102 such that the second roller 104 moves a predetermineddistance along the length of the tray 102 as the batten is raised andlowered.

The wire containment cable 101 can be connected to a lift cable, such asthe cables 31 described herein with reference to FIGS. 6-11 that windabout and unwind from the drum 58 in the lift system power head 22. Thewire cable lift cable 105 can be routed from the drum 58 to the wirecable lift cable loft block 106 near the end of the tube 11 opposite thepower head 22, around that loft block 106, and back in the oppositedirection toward the power head 22. The wire cable lift cable 105 can beattached at its distal end to the wire cable 101 and to the secondroller 104. As a result, the wire containment cable 101 can move in thesame direction and at the same rate as the lift cables 31 and the loadattached to the lift cables 31. As the lift cables 31 are wound onto thedrum 58, the second roller 104 moves toward the wire cable loft block106, and the wire cable lift cable 105 moves around the wire cable loftblock 106 and is likewise wound onto the drum 58 the same amount and atthe same rate as the lift cables 31 attached to the load, or article 21,are wound. As the lift cables 31 are unwound from the drum 58, the wirecable lift cable 105 is likewise unwound from the drum 58 and movesaround the wire cable loft block 106, allowing the second roller 104 tomove away from the wire cable loft block 106 and lower the wire cable101 the same amount and at the same rate as the lift cables 31 attachedto the load are lowered.

When the batten is in a lowered position, the wire containment cable 101can extend downward from the tray 102 around the first roller 103 to thebatten or load. In some embodiments of a method, as the load attached tothe lift cables 31 is raised, the wire cable 101 can be routed from itssubstantially vertical position, about the top of the first roller 103,and to a substantially horizontal position in the tray 102. The wirecable 101 can be guided about the top of the second roller 104 suchthat, as the load is raised, the wire cable 101 is positioned so as tolie flat in the tray 102. The wire containment cable 101 may be “singlepurchased” so as to be positioned in a single layer along the tray 102,or it may be “double purchased” so that the wire cable 101 is positionedhaving a second layer lying flat on top of a first layer in the tray102.

In a particular illustrative embodiment, such a method can includeconnecting one end of at least one of a plurality of wires to an inputsource and the opposite end of the at least one of the wires to anoutput object movable with the article 21 in the lift system 10. Theplurality of wires can be contained in the wire containment cable 101.The tray 102 can be connected along at least a portion of the length 16of the tube 11 and have dimensions for containing the wire containmentcable 101. The wire containment cable 101 can be moved between a first,substantially vertical position when the article 21 is fully lowered anda second, substantially horizontal position in the tray 102 when thearticle 21 is fully raised. The method can further include positioningthe wire containment cable 101 in a single layer in the tray 102 whenthe article 21 is fully raised.

Such an embodiment of the method can further include attaching therotatable first roller 103 to one end of the tray 102, and attaching themovable second roller 104 to the tray 102 that is movable apredetermined distance along a length of the tray 102 as the article 21is moved. The wire containment cable 101 can be attached to the secondroller 104 and to the wire cable lift cable 105 comprising one of theplurality of cables 31. The wire containment cable 101 can be guided bythe second roller 104 about a surface of the first roller 103 betweenthe first and second positions. In certain embodiments, the tube 11 canfurther include the wire cable loft block 106 located near an end of thetube 11 opposite the drive mechanism 22, and the wire cable lift cable105 can be routed from the drive mechanism 22 to and around the wirecable loft block 106 and back in the opposite direction to the secondand first rollers 104, 103, respectively.

FIG. 14 is a view of the compression tube 11, power head 22, particularload configuration, and the cable management system 100 in an embodimentof the lift assembly, or lift assembly system 10.

FIG. 15 is a view of a portion of an embodiment of the compression tube11. In such an embodiment, the tube 11 can provide a track foradjustable loft blocks 32; snap into and slide in beam clamp tubereceivers 118; absorb lateral forces on a building; be pre-rigged at thefactory and packaged in a single shippable unit; support terminal boxes;and/or house and track the cable management system 100.

As shown in FIGS. 14-16, in some embodiments, the compression tube 11may comprise a single piece of material having one or more upwardextensions 116 projecting substantially vertically upwardly from the top14 of the tube 11. The tube 11 may be extruded, or formed in anothermanner. The material of the tube 11 and/or the upward extensions 116 cancomprise aluminum and/or another material. These upward extensions 116can have a tapered and flanged tip 117 that enables the tube 11 to beinserted, or snapped into, and locked into the beam clamp tube receiver118, as shown in FIGS. 17 and 18. In addition, such a configurationhaving upward structural extensions 116 can give the tube 11 greaterdurability during shipping. In certain embodiments, the tube 11 mayinclude a T-shaped rail 120 or other configured addition on thehorizontal top 14 of the tube 11 that can be used to guide the cablemanagement system 100, as described herein. The compression tube 11 mayalso have a slotted rail 121 on either or both front 12 and rear 13 sidewalls that may be used to guide the loft blocks 32.

In some embodiments, the compression tube 11 may be able to slidehorizontally, that is longitudinally, in the beam clamp tube receivers118, and enable infinite positioning points of the tube 11 along theoverhead support structure 57. This allows easier installation, as theinstaller can mount the beam clamp tube receivers 118 first. Then aperson can hang a section of the tube 11, for example, by snapping thetube 11 into the beam clamp tube receiver 118, and sliding the tube 11in either direction perpendicular to the overhead support structure 57,and into other beam clamp tube receivers 118 at both ends of the tubesection. In this manner, the compression tube 11 can be mounted by asingle person by ascending a ladder or scaffold only once.

FIG. 16 is a view of an embodiment of a “sandwich” style compressiontube splicing clamp 112 useful for splicing together two abutting endsof compression tube 11 portions in some embodiments of the presentinvention. The splicing clamp 112 can comprise an upper plate 113 an alower plate 114 that can be tightened toward each other and onto theopposing slotted rails 121. Tightening of the plates 113, 114 may beaccomplished by a tightening mechanism 115, as shown in FIG. 16,configured to press against the ends of the tube 11 portions and securethe end portions together. The tightening mechanism 115 can be anysuitable tightening mechanism, for example, a threaded bolt or aratcheting collar. A roll pin can be included for aligning a cablemanagement tee guide. In certain embodiments, the clamp 112 can supportthe cable management system tray 102, and can provide a medium forrigidity and compression of the connected tube 11 portions. The ends ofthe tube 11 sections can be fastened to each other by tightening thesplicing clamp 112, as shown in FIG. 16, onto the slotted rails 121 oftwo abutting tube 11 sections.

FIG. 17 is a view of two beam clamp tube receivers 118 in an embodimentof the present invention. FIG. 18 is a view of the compression tube 11in position to be snapped into the overhead beam clamp tube receiver 118in an embodiment of the present invention. Sections of the compressiontube 11 can be inserted into the tube receiver 118 and then freely slidin a perpendicular direction relative to the overhead beam 57 and into adesired operating position. FIG. 19 is a view of the compression tube 11attached to two overhead beams 57 showing that the tube 11 can beattached to beams 57 at any location along the length 16 of the tube 11.The sliding beam clamps 118 can allow the compression tube 11 to absorball the horizontal loads placed on the building structure by the liftassembly 10. FIG. 20 is a view of the compression tube 11 positionedwithin the beam clamp assembly 118, showing that the tube 11 can easilyslide longitudinally within the beam clamp tube receiver assembly 118.In some embodiments, the beam clamp tube receiver 118 or the power head22 can be fixed in position so that as the tube 11 compresses, the samebeginning position of the lift system 10 on the overhead structure 57can be maintained.

As shown in FIGS. 17 and 18, in some embodiments, the beam clampassembly 118 can comprise two or more hooks 122 that can be tightenedtogether to squeeze on either side of a structural steel I-beam,unistrut, flanges, or other surface. Each hook 122 can comprise aU-shaped structure having two spaced-apart plates comprising a strong,rigid material, for example, steel. One beam clamp tube receiverassembly 118 can include four “hooks” 122. Each hook 122 can furtherinclude a U-shaped insert 123 having spaced-apart arms and be configuredto fit inside the hook 122 such that each arm of the insert 123 fitsadjacent to one of the spaced-apart plates of the hook 122. The topportion of the insert 123 can extend upward through an opening in thetop of the hook 122 and around a bolt 119 that secures the insert 123 inposition relative to the hook 122.

The inserts 123 can be adapted to receive the upward extensions 116 ofthe tube 11 so as to lock the upward extensions 116 inside the hook 122.This may enable the compression tube 11 to be snapped into the beamclamp 118 from the bottom of the beam clamp 118, while preventing thecompression tube 11 from falling from the grasp of the hooks 122. Incertain embodiments, the inserts 123 may be lined with a material, forexample, plastic, that may allow the compression tube 11 to slidelaterally with reduced friction and noise, and prevent galvaniccorrosion between dissimilar metals, such as steel comprising the beamclamp 118 and aluminum comprising the compression tube 11. In someembodiments, a clamping mechanism can be utilized to secure the loftblocks 32 to the tube 11.

In certain embodiments, each hook can include a clamp 125. The clamp 125can comprise two lengths of material shorter than the vertical interiorof the hook 122. Each of the two lengths of material can be positionedinside one of the spaced-apart opposing arms of the insert 123, and canbe configured to move a short distance up and down inside the hook 122,for example, about one-fourth inch. The clamp 125 can comprise adeformable material, such as a plastic, that can be forced open by thetapered tip 117 of the tube upward extension 116. Once the tube tip 117is inserted into the hook 122 above the top of the clamp 125, the flange126 on each side of the tip 117 can rest on top of the two verticallengths of the clamp 125. The weight of the lift assembly 10 can pullthe tube 11 and the clamp 125 in a downward direction. Each hook 122 mayhave a pair of opposing bottom tapered edges 124 to prevent the clamp125 from moving downward below the bottom tapered edge 124 under theweight of the inserted tube 11. In this manner, the compression tube 11can be locked into the clamp 125 and the hook 122 so as to prevent thecompression tube 11 falling out of the beam clamp tube receiver 118.

FIG. 21 is a view of one embodiment of a loft block 32 that isself-locking, useful in the lift assembly system 10 of the presentinvention. As shown in FIG. 21, in some embodiments, the loft blockassembly 32 can comprise a pulley that can slide longitudinally withinthe tube 11. The loft block assembly 32 may be able to be tilted up outof locked position within the tube 11 in order to allow it to be movedback and forth in the tube 11 by hand. Once the loft block assembly 32is positioned at a desired point along the length 16 of the tube 11, theassembly 32 can be tilted back down and locked onto, for example, theslotted rails 121, inside the tube 11. The loft block 32 may be lockedin place due to gravity, friction, and any other force than may cause itto wedge itself against the compression tube 11, rendering itstationary.

In certain embodiments, the loft block assembly 32 may include wheels orslides 45, 47, as shown in FIG. 5, to facilitate moving the loft blockassembly 32 when desired. The wheels or slides 45, 47 may comprise aslidable material such as plastic. The wheels or slides 45, 47 may nolonger touch the compression tube 11 once the loft block assembly 32 hasbeen set in position within the tube 11. In such embodiments, the loftblock assembly 32 can be easily moved within the tube 11 such that theloft block assembly 32 does not require tight tolerances for providing alocking mechanism.

The loft block assembly 32 can comprise an aluminum surface, which, whenin position in contact with the compression tube 11 (also comprising analuminum surface), the friction coefficient increases as a force isapplied to the assembly 32, further locking it in position against thetube 11. In addition, as weight or load is placed on an attached cable31, the cable 31 tends to force the loft block 32 to pivot through thecompression tube, which further secures the loft block assembly 32 inits position in the tube 11.

FIG. 22 is a view of the power head 22 attached to the compression tube11, and loft blocks 32 loaded in the tube 11 in an embodiment of thepresent invention. FIG. 23 is a view of the progressively sloped drum 58and the brake disk 85 in an embodiment of the lift assembly system 10 ofthe present invention.

As shown in FIGS. 22 and 23, in some embodiments, the cables 31, or wireropes, can wind around the progressively sloped drum 58. Such aprogressive drum 58 can allow the cables 31 to wind around each other,saving horizontal travel distance. As the cables 31 wind on the drum 58,they may move up a slope, but can wrap about a horizontal plane for someof the distance. In certain embodiments, a cable keeper 127, forexample, a flat piece of material, such as aluminum, can rest on thishorizontal portion of the wound cables 31, serving to keep the cables 31from unraveling from the drum 58 in the event that one might go slack.The cable keeper 127 can include an arm 128 extending outward to contacteach cable 31 on the drum 58. The cable keeper arm 128 can bespring-loaded in a biased fashion against the cables 31. One end of thecable keeper 127 can be attached to a guide mechanism 130 that travelslaterally at the same rate as the cables 31 wind onto the drum 31. Thecable keeper 127 can be attached by a spring that keeps enough pressureon the cables 31 to keep the cables 31 positioned about the drum 58, butwithout so much force as to affect the natural winding and unwinding ofthe cables 31 about and from the drum 58. The cable keeper 127 can movealong with the guide assembly 86 across the constant diameter portion 64and the increasing diameter portion 63 of the drum 58.

In certain embodiments, the guide mechanism 130 can be connected to athreaded rod 131, which can be connected to the drive shaft 28 with achain and sprockets. The chain and sprockets can be geared so as to makethe guide mechanism 130 move laterally at the same rate as the cables 31wind laterally about the progressively sloped drum 58.

In certain embodiments, as the guide mechanism 130 moves laterally alongthe threaded rod 131, switches can be positioned at fixed points on thethreaded rod 131. FIG. 24 is a view of a low limit switch 132 and a highlimit switch 133 useful in embodiments of the present invention. Theselimit switches 132, 133 can be miter-geared switches. These switches132, 133 can be tripped to send a signal to the controls of the liftsystem 10 that the load such as a batten, has reached its upper, orfully raised limit, or it fully lowered limit. These limit switches 132,133 can be easily adjusted by turning a miter-geared threaded rod. Thelimit switches 132, 133 can be oriented such that they are angled andoff-set from the cables 31 and drum 58. For example, the most extremetravel of the drum 58 can be set by one adjuster that moves the relativeposition of two switches to a striker. The first switch 132, 133 engagedby the striker can send a stop signal to the controls. If that switchfails, a second, or back up, switch can be struck and send a signal,preventing single-mode failure of the guide mechanism 130.

FIG. 25 is a view of the cable keeper 127, a slack line detector 152,and a dynamic load transducer in an embodiment of the present invention.As shown in FIG. 25, the slack line detector 152 can include sensorsthat may be used to monitor a slack line condition. A slack linecondition can occur if one or more of the cables 31 lose tension. Thiscould happen if the batten is accidentally lowered onto an object on thestage floor. Each cable 31 may pass off the drum 58, through the guidemechanism 130, under the slack line detector 152, and then out into thetube 11. The slack line detector 152 can include a slack line sensor arm153, for example, a plastic slat, for each cable. The slat 153 may behave an off-centered pivot point, with an adjustable spring holding oneend of the slat 153 down. The other end of the arm 153 may be positionednext to a switch, so that if the end near the switch is raised, it willtrip the switch, which can relay a message to the controls of the liftsystem 10 to stop the batten until the slack line problem is resolved.If one of the cables 31 becomes slack, the lack of tension may cause thecable 31 to try to rise out of the guide mechanism 130. The cable 31 canthen touch the plastic arm 153, causing the arm 153 to pivot, therebytripping the switch. In this manner, each cable 31 can have a dedicatedsensor arm 153 that is pivotable for actuating a limit switch to managea slack cable. In certain embodiments, the pivotable arms 153 can bepositioned in locations other than near the drum 58.

In some lift assemblies 10, the wire cable lengths may be slightlydifferent and/or the batten or load may be uneven across its horizontallength. In some conventional lift assemblies, the cable lengths can betrimmed with a turnbuckle positioned between each cable 31 and thebatten. Turnbuckles are typically vertically oriented along the drop ofthe cable 31 from the loft block 32 to the batten. Turnbuckles can oftenhave a length of at least 6 inches and up to 14 inches or more at theirmaximum spread. Thus, vertically oriented turnbuckles can require addedvertical distance, or height, between the overhead point at which loftblocks 32 are secured to a building and the lowest point at which thebatten can be lowered. Every inch of additional height required by alift assembly can be important, as it can mean a higher roof in abuilding, which can add significant costs to construction.

Some embodiments of the present invention can include a low profile,horizontally oriented cable adjuster 134 as an interface between thecables 31 and the batten. FIGS. 26-29 illustrate various embodiments ofsuch a low profile, horizontal cable adjuster 134. For example, as shownin FIGS. 26-29, the cable adjuster 134 can include a pair of cable guidemechanisms 135, 137. A first one of the cable guide mechanisms 135 canbe attached to a first rigid plate 136 and include a cable pathwayhaving an angle, for example, a 90 degree angle. A second one of thecable guide mechanisms 135 can be attached to a second rigid plate 138spaced apart along a horizontal axis from the first plate 136 andinclude a cable pathway angle, for example, a 180 degree angle. In someembodiments, for example, as shown in FIGS. 26-28, the cable guidemechanisms 135, 137 having 90 degree angle and 180 degree angle cablepathways, respectively, can comprise a tubular material such as steelbent at those angles.

In some embodiments, the first plate 136 can be attached to a U-shapedsupport 140. The 90 degree cable guide tube 135 may be further attachedto the U-shaped support 140, such that the U-shaped support 140 can bemoved vertically along with the cable 31. One or more securing bolts 141can pass through holes in each of the arms 142 of the U-shaped support140. In certain embodiments, a batten attachment arm 143 can be securedto the U-shaped support 140 with the securing bolts 141. The secondplate 138 can have various shapes and dimensions configured to providesupport to the 180 degree cable guide mechanism 137. For example, asshown in the embodiments in FIGS. 26-28, the second plate 138 can beU-shaped and attached to the ends of the 180 degree cable guide tube137. The cable adjuster assembly 134 can be strong enough to support abatten and/or a load attached to the cable 31.

As shown in FIGS. 26-29, the cable 31 can be routed vertically from thepower head 22, through the 90 degree cable guide mechanism 135,horizontally into a cable entry point 144 in one end of the 180 degreecable guide mechanism 137 in a first horizontal direction, out of the180 degree cable guide mechanism 137 in the opposite horizontaldirection, and dead end at a cable attachment point 146 on the firstplate 136 attached to the 90 degree cable guide mechanism 135. The cable31 can be securely attached to the first plate 136 in a variety of ways.For example, the cable 31 can be attached to the first plate 136 using a“nico” fitting or a “swage” fitting.

In some embodiments, the cable adjuster assembly 134 can further includea horizontal adjustment bolt 147, or threaded rod, or other mechanismconfigured to maintain a desired distance between the first and secondplates. The adjustment bolt 147 can help hold the assembly together. Oneend of the bolt or threaded rod 147 can be secured to the 180 degreecable guide mechanism 137. As shown in FIGS. 26-29, the horizontaladjustment bolt 147 can be attached to the second plate 138 attached tothe 180 degree cable guide mechanism 137. The bolt 147 can be rotated tomove the 180 degree cable guide mechanism 137 horizontally, therebymoving the cable 31 horizontally and moving the entire cable adjusterassembly 134 vertically on the cable 31. In this manner, the length ofthe cable 31 between the loft block 32 and the attached article 21 canbe adjusted, that is lengthened or shortened. In some embodiments, thehorizontal adjustment mechanism can comprise distance adjustmentstructures other than a bolt or rod.

The cable pathway through the guide mechanisms 135, 137 can bedimensioned for a particular cable diameter, or range of cablediameters, with sufficient clearance between the cable 31 and the insidewall of the guide mechanisms 135, 137 such the cable 31 can movesmoothly through the guide mechanisms 135, 137 without undesirablefriction, or drag. For example, the inside diameter of the cable pathwaythrough the guide mechanisms 135, 137 can be large enough for a 3/16inch and/or a ¼ inch cable 31. In some embodiments, the inside diameterof the cable pathway through the guide mechanisms 135, 137 can be largeror smaller, depending on the diameter of the cable 31 to be guidedthrough the guide mechanisms 135, 137. That is, for a cable 31 having adiameter smaller than 3/16 inch, or for a cable 31 having a diameterlarger than ¼ inch, the diameter of the cable pathway can be just largeenough to accommodate that particular size cable 31.

The 180 degree guide mechanism 137 can have a spread 148 between thecable entry point 144 and the cable exit point 145 that provides a cablepath that is sufficiently rounded, or arched, to reduce friction betweenthe cable 31 and the guide mechanism 137. In certain embodiments, forexample, the spread 148 of the cable path in the 180 degree guidemechanism 137 can be about two inches. That is, as shown in FIGS. 26-29,the distance between the cable entry point 144 into the 180 degree guidemechanism 137 and the cable exit point 145 from the 180 degree guidemechanism 137 can be about two inches. In some embodiments, thedistance, or spread 148, between the cable entry point 144 into and thecable exit point 145 from the 180 degree guide mechanism 137 can be moreor less than two inches, depending on various factors, including, forexample, the differential between the diameter of the cable 31 and theinside diameter of the guide mechanism cable pathway, the materials fromwhich each of the cable 31 and the inside walls of the guide mechanismcable pathway are made, and other factors. The relative sizes of thecable 31 and the cable pathway in the guide mechanisms 135, 137 and thespread of the cable 148 entering and exiting the 180 degree guidemechanism 137 can be dimensioned so as to maintain the structuralintegrity of the cable 31 and the cable pathway during repeated use.

The cable adjuster assembly 134 may be only a few inches tall, forexample, two to four inches tall, which could save six or more inches ofvertical distance, as compared to conventional lift assembly cableadjusters using vertically oriented turnbuckles. The cable adjuster 134may be used to trim the cables 31 that hold the batten, effectivelyleveling the batten if one or more cables 31 are longer than another, orif the batten is loaded unevenly such that one end is heavier than theother. In this manner, the low profile, horizontally oriented design ofthe cable adjuster 134 of the present invention can eliminate thesignificant cost for building a foot or more of vertical space requiredin a building by other lift assembly systems.

In another embodiment of the low profile, horizontally oriented cableadjuster 134, the cable guide mechanisms 135, 137 can comprise a pair ofguide blocks 150, 151 instead of angled tubes. FIG. 29 illustrates oneembodiment of such a cable adjuster 134 having guide blocks 150, 151. Inthis embodiment, the first guide block 150 includes a 90 degree anglecable pathway, and the second guide block 151 includes a 180 degreeangle cable pathway. In such a configuration, the guide blocks 150, 151can guide the cable 31 from a vertical direction from the loft block 32into a first horizontal direction and then into a second, oppositehorizontal direction. In this manner, the cable adjuster 134 can providea low profile mechanism for adjusting the cable 31 in the verticaldirection so as to trim the cable 31.

In some embodiments, the cable guide blocks 150, 151 can comprisevarious materials. Such materials can be advantageously lightweight,strong, and inexpensive. One such material is plastic. In otherembodiments, the guide blocks 150, 151 can comprise aluminum, steel, orother suitable load-bearing materials. The guide blocks 150, 151 can bemade in various ways. For example, the guide blocks 150, 151 can bemolded, or cast. As the guide blocks 150, 151 are made, the cablepathways can be formed within the guide blocks 150, 151.

The guide blocks 150, 151 can be securely attached to the first andsecond plates 136, 138, respectively. In certain embodiments, the guideblocks 150, 151 can be securely bolted or welded to the plates 136, 138and/or supports. For example, as shown in FIG. 29, at least one of thesecuring bolts 141 can be inserted through the 90 degree angle cableguide block 150 to securely attached the guide block 150 to the U-shapedsupport 140 to which the first plate 136 is attached.

In other embodiments (not shown), the 180 degree guide mechanism 137 caninclude a pulley mechanism.

Some embodiments of the lift assembly system 10 and method can includean “overspeed” braking mechanism 154 on the load side of the system 10.Such a load-side, overspeed braking mechanism 154 can serve as a back-upbraking mechanism for the brake 36. The overspeed braking mechanism 154can comprise a brake rotor, or disk 85, positioned on the drive shaft 28of the motor 27. In the embodiment shown in FIGS. 30 and 31, the brakedisk 85 has been removed to show other portions of the braking mechanism154. In certain embodiments, the braking mechanism 154 can include acaliper-type brake. Such a caliper-type brake can include a brake padhousing 155 having a fixed brake pad 156 and a moveable brake pad 157.The moveable brake pad 157 can move toward the fixed brake pad 156 so asto compress against the brake disk 85 to slow and/or stop rotation ofthe drive shaft 28 and the attached cable drum 58.

The overspeed braking mechanism 154 can further include a brake shoe 158adapted to move up and down on a ramp 160. When the article 21, or otherload, is being raised in the lift system 10, the brake disk 85 moves inthe counterclockwise direction to a more narrow portion of the ramp 160and away from the surface of the ramp 160. This movement allows thebrake shoe 158 to remain free from compressing the moveable brake pad157, thereby allowing the brake disk 85 and the load to move freelyunder the power of the motor 27. The overspeed braking mechanism 154 canfurther include a spring 159 connected between the top of the brake shoe158 and the top of the brake pad housing 155. In this configuration, thespring 159 can provide a bias against the brake shoe 158. While thearticle 21 is being raised, the spring 159 is biased against the brakeshoe 158 so as to provide a “pre-load” on the brake shoe 158. In thismanner, if power of the motor 27 is lost and the cables 31 and attachedarticle 21 began to free fall, the spring 158 can push the brake shoe158 to compress the moveable brake pad 157 toward the fixed brake pad156 and exert friction against the brake disk 85 between the brake pads156, 157, thereby slowing and/or stopping fall of the article 21.

When the article 21, or other load, attached to the cables 31 is beinglowered in the lift system 10, gravity on the load causes the brake disk85 moving in a clockwise direction to move to a wider portion of theramp 160 and press against the ramp 160. This movement of the brake shoe158 causes it to compress the moveable brake pad 157 onto the brake disk85 and against the fixed brake pad 156 into a position capable ofslowing and/or stopping movement of the cables 31. Thus, when the cables31 and attached article 21 are being lowered, the brake disk 85 isfrictionally engaged between the moveable brake pad 157 compressedtoward the fixed brake pad 156. However, the power of the motor 27 canbe greater than the coefficient of friction of the brake disk 85 betweenthe compressed moveable brake pad 157 and the fixed brake pad 156 sothat the article 21 can continue to be lowered. If power of the motor 27is lost and the cables 31 and attached article 21 began to free fall,the spring 158 can push the brake shoe 158 to compress the moveablebrake pad 157 toward the fixed brake pad 156 and maintain friction ofthe brake pads 156, 157 against the brake disk 85, thereby slowingand/or stopping fall of the article 21. The “pre-load” push provided bythe spring 159 may provide the additional friction on the brake disk 85to cause the article 21 to be completely stopped, rather than onlyslowing, in the event of a loss of motor power.

The overspeed braking mechanism 154 can include a brake release arm 161.The brake release arm 161 can be pivotable about a pivot 162. Thepivoting end of the brake release arm 161 extends outward so that aplate (not shown) on the motor 27 can push downward on the arm 161 whenthe motor 27 tilts slightly downward with the drive shaft 28 after themotor 27 stops rotating but before the gravitational force of the causesthe drive shaft 28 to begin rotating again. This decreases thesuddenness, or “shock” to the system, of having to release the brake 154quickly.

In certain embodiments, the brake disk 85 can comprise a surfacematerial having a high friction coefficient. For example, the brake disksurface material can comprise steel or cast iron such that the frictionbetween the brake pads 156, 157 and the disk 85 is enhanced. Thefrictional interface between the brake disk 85 and the brake pads 156,157 can help the brake disk 85 (and the motor 27) slow to a stop, ratherthan stopping undesirably abruptly. This can allow the overspeed brakingmechanism 154 to be released more gradually and the article 21 beinglowered by the lift system 10 to be stopped more gradually in the lastfew feet of descent in the event that the overspeed brake 154 isactivated.

Some embodiments of the lift assembly system 10 and method can furtherinclude a fleet pivot arm 163. As shown in FIG. 32, the fleet pivot arm163 can be pivotably attached to the tube 11 and drive mechanism, orpower head, housing 23. The fleet pivot arm 163 can comprise a U-shapedarm having an upper pulley, or block 164, adjacent the tube 11 and alower pulley, or block 165, adjacent the power head 22. A pivot rod 166can extend outward from the tube 11 in axial alignment with thelongitudinal axis of the tube 11. The upper U-shaped portion of thefleet pivot arm 163 can be pivotably attached about a pivot point 167 onthe pivot rod 166 such that the lower portion of the fleet pivot arm 163can pivot in a direction substantially perpendicular to the longitudinalaxis of the tube 11. The upper U-shaped portion of the fleet pivot arm163 can include bearings that provide a pivotable interface with thepivot rod 166.

A pivot plate 168 can be attached to the end of the drive mechanismhousing 23 to provide a rigid surface on which the fleet pivot arm 163can contact as it pivots. The fleet pivot arm 163 can include a roller170 on the inside of the arm 163 opposite the lower block 165 andadjacent the pivot plate 168. As the fleet pivot arm 163 pivots, theroller 170 can roll against the pivot plate 168 to provide a smoothmovement of the pivot arm 163 back and forth. In certain embodiments,the fleet pivot arm 163 can include two or more rollers 170 that canroll against the pivot plate 168 as the pivot arm 163 pivots. In someembodiments, the roller 170 can have a cylindrical shape. In otherembodiments, the roller 170 can have a conical shape that canaccommodate movement of the fleet pivot arm 163 in an arc as it pivotsabout the pivot rod 166.

In operation, the cables 31 can be routed from the drum 58 around thelower block 165, then upward to the upper block 164, and finally intothe tube 11 to the respective loft blocks 32. The upper and lower blocks164, 165, respectively, on the fleet pivot arm 163 can rotate freely. Asthe cables 31 are unwound from the drum 58, the fleet pivot arm 163 canpivot in response to the angle at which the cables 31 are paying outfrom the drum 31. In this manner, the pivoting of the fleet pivot arm163 can help guide the cables 31 along a desired fleet angle as thecables 31 are unwound from and wound onto the drum 58. Embodiments ofthe fleet pivot arm 163 may be particularly advantageous in a liftsystem in which the drum 58 is a funnel-shaped, or progressive diameter,drum as shown in FIGS. 6-11 and 23. Since the fleet angle of the cables31 at the point at which they travel into and out of the tube 11 odesnot change, the upper block 164 near the pivot point 167 does not needto move except minimally.

Some embodiments of the lift assembly system 10 and method can furtherinclude a load sensor mechanism 171. In some embodiments, the loadsensor mechanism 171 can comprise a compression load cell sensor (notshown) positioned between the tube 11 and the power head 22. Thecompression load sensor mechanism 171 can be used to measure the load onthe batten by sensing the forces trying to move the power head 22 andcompression tube 11 toward each other. This can be useful to monitorchanges in the load on the batten, such as if the batten were to becomecaught on a curtain or other obstruction. If the load sensor mechanism171 senses a change in the load, it can relay a message to the liftsystem control system to slow and/or stop operation of the lift system10 until the problem has been resolved. In certain embodiments, the loadsensor mechanism 171 can be mounted between the tube 11 and the drivemechanism housing 23. The load sensor mechanism 171 can be configured asa button that is actuated by compressing when the tube 11 and the powerhead 22 move closer to each other due to load forces exerted by movementof the article 21 attached to the cables 31.

In another embodiment, the interface between the tube 11 and the drivemechanism housing 23 can comprise a slide plate 174 configured to slideon a set of rails 173 between the tube 11 and the drive mechanismhousing 23. The load sensor mechanism 171 can be operably attached tothe slide plate 174 such that increased load forces due to movement ofthe article 21 can cause the slide plate 174 to slide on the rails 173and compress a button sensor to actuate the sensor and adjust movementof the load as needed. In another embodiment, the interface between thetube and the drive mechanism housing 23 can comprise a moveable hinge towhich the load sensor mechanism 171 is operably attached. The hinge canallow the tube 11 and the power head 22 to move toward each other,thereby compressing the load sensor mechanism 171 and adjusting movementof the load as needed.

In other embodiments of the lift assembly system 10 and method,monitoring and controlling movement of the load can be accomplished bythe load sensor mechanism 171 comprising a pull-type load sensor (alsoreferred to as an S-type load sensor), as shown in FIG. 33. Thepull-type load sensor can be used to measure changes in the load on thebatten by sensing the forces attempting to pull the tube 11 away fromthe drum 58. As shown in FIG. 33, such a load sensor mechanism 171 caninclude a load sensor 172 mounted between the tube 11 and the drum 58comprising a first portion 175 and a second portion 176, each portion175, 176 adapted to be pulled against the other, thereby sensing changesin a load force on the article 21 attempting to pull the tube 11 awayfrom the drum 58. In this manner, the sensor 172 can sense changes inthe load force and signal controls in the lift assembly system 10 toadjust movement of the article 21.

In some embodiments, the load sensor mechanism 171 can further include aset of slide rails 173 attached between the drive shaft 28 and drum 28in the drive mechanism housing 23 and the tube 11. A load cell slideplate 174 can be slidably mounted on the slide rails 173. The pull-typeload cell sensor 172 can be operably attached between the slide plate174 and the drive shaft 28 and drum 58. Increased load forces due tomovement of the article 21 can cause the slide plate 174 to slide on therails 173 away from the drive shaft 28 and drum 58 and pull the loadsensor 172 to actuate the sensor 172 and adjust movement of the load asneeded. In particular embodiments, the lift assembly system 10 caninclude the slide rails 173, slide plate 174, and pull-type load sensor172 on the drive shaft 28 on each side of the drum 58.

Embodiments of components of the lift assembly system 10 and methods maybe advantageously utilized in other lift systems and methods. Forexample, the hybrid funnel-shaped, progressive diameter drum 58, thecable management system 100, the splicing clamp 112, the beam clamp tubereceiver 118, the self-locking loft block 32, the cable keeper 127, theslack line detector 152, the low profile cable adjuster 134, theoverspeed braking mechanism 154, the fleet pivot arm 163, and/or thepull-type load sensor 172 may be utilized alone or in combination inother lift systems.

Some embodiments of the present invention include a lift system,comprising: a substantially rectangular tube having an opening in abottom along at least a portion of a length of the tube, and connectableto an overhead structure; a drive mechanism connected externally on oneend of the tube; a funnel-shaped drum operably connected to the drivemechanism and adapted to wind and unwind a plurality of cables about thedrum to raise and lower an article attached to the cables; and aplurality of loft blocks connected to the tube internally so as toredirect the cables from a generally horizontal path from the drum to agenerally vertical path through the bottom opening in the tube to theattached article.

In such embodiments, the drum can further comprise: an apex having afirst diameter and a base having a second diameter larger than the firstdiameter; a constant diameter portion having the first diameter andextending from the apex; a gradually increasing diameter portionextending from the constant diameter portion to the base; a plurality ofdiscrete circumferential channels in the constant diameter portion, eachchannel adapted to route and maintain one of the cables in apredetermined position about the drum; and a first one of the channelsadjacent the gradually increasing diameter portion extending in acircumferential pattern about the gradually increasing diameter portion,wherein a first one of the cables is windable in the first channel aboutthe constant diameter portion and the gradually increasing diameterportion to the base.

In some such embodiments, when the first cable is wound about the drum,notches are formed between adjacent coils of the first cable, wherein asecond cable is windable in a second channel adjacent the first channeland into succeeding notches in the coils of the first cable, and whereinsucceeding cables are windable in succeeding adjacent channels in theconstant diameter portion and into succeeding adjacent notches in coilsof an adjacent wound cable.

In some such embodiments, each of the cables is windable about the drumsubstantially simultaneously.

Some such embodiments can further comprise a cable guide assemblycomprising a movable guide block having a guide hole for each of thecables and operably connected to the drum such that the guide block canmove at substantially the same angle as the drum to guide the cables asthey are wound onto and unwound from the drum.

Some embodiments of the present invention include a lift system,comprising: a plurality of wires, one end of at least one of the wiresconnectable to an input source associated with the drive mechanism andthe opposite end of the at least one of the wires connectable to anoutput object movable with the article; a wire containment cable forcontaining the plurality of wires; and a tray connected along at least aportion of a length of the tube and having dimensions for containing thewire containment cable, wherein the wire containment cable is movablebetween a first, substantially vertical position when the article isfully lowered and a second, substantially horizontal position in thetray when the article is fully raised.

In some such embodiments, when the article is fully raised, the wirecontainment cable comprises a single layer in the tray.

In some such embodiments, the tray is connected to the top of thearticle.

In some such embodiments, the lift system can further comprise: a firstroller rotatingly attached to one end of the tray; and a second rollermovably attached to the tray and movable a predetermined distance alonga length of the tray as the article is moved, wherein one of theplurality of cables comprises a wire cable lift cable, wherein the wirecontainment cable is attached to the second roller and to the wire cablelift cable, and wherein the wire containment cable is guided by thesecond roller about a surface of the first roller between the first andsecond positions.

In some such embodiments, the lift system can further comprise a wirecable loft block located near the end of the tube opposite the drivemechanism, wherein the wire cable lift cable is routed from the drum toand around the wire cable loft block and back in the opposite directionto the second and first rollers.

Some embodiments of the present invention include a lift system,comprising: the tube further comprising a plurality of lengthwiseportions connectable to each other end to end; and a splicing clampcomprising an upper plate and a lower plate adapted to receive andtighten about two abutting ends of the tube portions.

Some embodiments of the present invention include a lift system,comprising: a beam clamp tube receiver comprising a pair of opposinghooks adapted to be tightened together securely onto opposite sides ofthe overhead structure, and at least two opposing inserts movablevertically inside each hook and spreadable so as to receive the tube andlock together after the tube is received.

In some such embodiments, the tube can further comprise an upwardextension comprising a tapered tip having a flange adapted to securelyengage the beam clamp tube receiver; wherein each hook further comprisesa pair of opposing clamps movable vertically inside the hook; andwherein when the upward extension is inserted into the hook, the clampsare moved up and forced open by the tapered end of the tip and the tipflange rests on top of the clamps to lock the tube into the beam clamptube receiver.

In some such embodiments, the tube is slidable in the beam clamp tubereceiver in a direction perpendicular to the overhead structure to whichthe beam clamp tube receiver is attached.

In some such embodiments, the inserts further comprise afriction-reducing plastic material.

Some embodiments of the present invention include a lift system, whereinat least one of the loft blocks further comprises a self-locking loftblock, tiltable out of locked position so that the loft block can berepositioned along the length of the tube and tiltable back into lockedposition.

In some such embodiments, the lift system can further comprise a slottedrail on the inside of at least one of a front and a back of the tubeadapted to guide a loft block.

Some embodiments of the present invention include a lift system,comprising: a cable keeper comprising an arm extending across theconstant diameter portion and the increasing diameter portion of thedrum along an axis of the cables and biased against the drum so as tomaintain the cables in position about the constant diameter portion inthe event of loss of tension in one or more of the cables.

In some such embodiments, an end of the cable keeper is attached to aguide mechanism movable across the constant diameter portion of the drumat the same rate as the cables wind onto and unwind from the drum.

In some such embodiments, the guide mechanism further comprises: a lowlimit switch adapted to sense a degree of unwinding of the cables as anindicator of when the article has been fully lowered; and an upper limitswitch adapted to sense a degree of winding of the cables as anindicator of when the article has been fully raised.

Some embodiments of the present invention include a lift system,comprising: a slack line detector comprising a slack line sensor armbiased against one of the cables and movable in response to a loss oftension on the cable; and a switch responsive to movement of the sensorarm and adapted to adjust movement of the cables.

Some embodiments of the present invention include a lift system,comprising: a low profile cable adjuster comprising a first cable guideattached to a first plate and having a 90 degree angle cable path; asecond cable guide attached to a second plate horizontally spaced fromthe first cable guide and having a 180 degree angle cable path; and ahorizontal adjustment mechanism attached to the first and second platesconfigured to maintain an adjustable distance between the first andsecond plates, wherein the cable can be routed vertically from the loftblock into the first cable guide, out of the first cable guide in afirst horizontal direction into one end of the second cable guide, andout of the second cable guide in a second, opposite horizontal directionto an attachment point on the first plate, and wherein the horizontaladjustment mechanism is adjustable to change a length of the cablebetween the loft block and the article.

Some embodiments of the present invention include a lift system, inwhich the drive mechanism further comprises a drive shaft rotatinglyconnected to a motor, and the lift system further comprises: anoverspeed braking mechanism having a brake disk attached to the driveshaft rotatingly positioned between a moveable brake pad moveable towarda fixed brake pad; and a brake shoe attached to the moveable brake padand configured to move up on a ramp when the article is being lowered tocompress against and stop rotation of the brake disk and drive shaft andto move down on the ramp when the article is being raised to allowrotation of the brake disk and drive shaft.

In some such embodiments, the drive shaft and the motor are configuredto tilt downward after the overspeed braking mechanism causes the driveshaft to stop, the overspeed braking mechanism further comprising apivotable brake release arm configured for actuation by the motor whenthe motor tilts downward so as to gradually release the overspeedbraking mechanism.

Some embodiments of the present invention include a lift system,comprising: a fleet pivot arm pivotably attached to an end of the tubeabove the drive mechanism having an upper block adjacent the tube and alower block adjacent the drive mechanism such that the lower block canpivot in a direction substantially perpendicular to a longitudinal axisof the tube, wherein the fleet pivot arm is pivotable so as to guide thecables along a desired fleet angle as the cables are unwound from andwound onto the drum.

In some such embodiments, the lift system further comprises: a pivotplate attached to a drive mechanism housing; and a roller on an insideof the fleet pivot arm adjacent the lower block configured to rollagainst the pivot plate as the fleet pivot arm pivots.

Some embodiments of the present invention include a lift system,comprising: a load sensor connected between the drive mechanism and thedrive mechanism housing and comprising a first portion and a secondportion, each portion adapted to be pulled against the other, therebysensing changes in a load force on the article attempting to pull thedrive mechanism away from the drive mechanism housing, wherein thesensor is adapted to adjust movement of the article when changes in theload force are sensed.

In some such embodiments, the lift system further comprises: a set ofslide rails attached between the tube and the drive shaft; and a loadsensor slide plate slidably mounted on the slide rails, wherein the loadsensor is operably attached to the load sensor slide plate, and whereinan increased load force on the article causes the slide plate to bepulled away from the drive shaft and drum, and the first and secondportions of the load sensor to be pulled against each other.

Some embodiments of the present invention include a lift system drum,comprising: a funnel-shaped drum comprising an apex having a firstdiameter and a base having a second diameter larger than the firstdiameter; a constant diameter portion having the first diameter andextending from the apex; and a gradually increasing diameter portionextending from the constant diameter portion to the base, wherein thedrum is adapted to wind and unwind a plurality of cables about the drumto raise and lower an article attached to the cables.

In some such embodiments, the lift system drum can further comprise: aplurality of discrete circumferential channels in the constant diameterportion, each channel adapted to route and maintain one of the cables ina predetermined position about the drum; and a first one of the channelsadjacent the gradually increasing diameter portion extending in acircumferential pattern about the gradually increasing diameter portion,wherein a first one of the cables is windable in the first channel aboutthe constant diameter portion and the gradually increasing diameterportion to the base.

In some such embodiments of the lift system drum, when the first cableis wound about the drum, notches are formed between adjacent coils ofthe first cable, wherein a second cable is windable in a second channeladjacent the first channel and into succeeding notches in the coils ofthe first cable, and wherein succeeding cables are windable insucceeding adjacent channels in the constant diameter portion and intosucceeding adjacent notches in coils of an adjacent wound cable.

In some such embodiments of the lift system drum, each of the cables iswindable about the drum substantially simultaneously.

Some embodiments of the present invention include a lift system cablemanagement system, comprising: a plurality of wires, one end of at leastone of the wires connectable to an input source and the opposite end ofthe at least one of the wires connectable to an output object movablewith an article; a wire containment cable for containing the pluralityof wires; and a tray connected along at least a portion of a length of asubstantially rectangular tube connectable to an overhead structure, thetray having dimensions for containing the wire containment cable;wherein the wire containment cable is movable between a first,substantially vertical position when the article is fully lowered and asecond, substantially horizontal position in the tray when the articleis fully raised.

In some such embodiments of the lift system cable management system,when the article is fully raised, the wire containment cable comprises asingle layer in the tray.

In some such embodiments of the lift system cable management system, thetray is connected to a top of the article.

Some such embodiments of the lift system cable management system canfurther comprise: a first roller rotatingly attached to one end of thetray; and a second roller movably attached to the tray and movable apredetermined distance along a length of the tray as the article ismoved, wherein one of the plurality of cables comprises a wire cablelift cable, wherein the wire containment cable is attached to the secondroller and to the wire cable lift cable, and wherein the wirecontainment cable is guided by the second roller about a surface of thefirst roller between the first and second positions.

Some such embodiments of the lift system cable management system canfurther comprise a wire cable loft block located near the end of thetube opposite the drive mechanism, wherein the wire cable lift cable isrouted from the drum to and around the wire cable loft block and back inthe opposite direction to the second and first rollers.

Some embodiments of the present invention include a beam clamp tubereceiver, comprising: a pair of opposing hooks adapted to be tightenedtogether securely onto opposite sides of an overhead structure; and atleast two opposing inserts movable vertically inside each hook andspreadable so as to receive a substantially rectangular tube and locktogether after the tube is received.

In some such embodiments of the beam clamp tube receiver, the tube isslidable in the beam clamp tube receiver in a direction perpendicular tothe overhead structure to which the beam clamp tube receiver isattached.

Some embodiments of the present invention include a low profile cableadjuster, comprising: a first cable guide attached to a first plate andhaving a 90 degree angle cable path; a second cable guide attached to asecond plate horizontally spaced from the first cable guide and having a180 degree angle cable path; and a horizontal adjustment mechanismattached to the first and second plates configured to maintain anadjustable distance between the first and second plates, wherein thecable can be routed vertically from the loft block into the first cableguide, out of the first cable guide in a first horizontal direction intoone end of the second cable guide, and out of the second cable guide ina second, opposite horizontal direction to an attachment point on thefirst plate, and wherein the horizontal adjustment mechanism isadjustable to change a length of the cable between a loft block in alift system and an article to which the cable is attached.

Some embodiments of the present invention include an overspeed brakemechanism, comprising: a brake disk attached to a drive shaft operablyconnected to a motor and rotatingly positioned between a moveable brakepad moveable toward a fixed brake pad; and a brake shoe attached to themoveable brake pad and configured to move up on a ramp when the motor isunwinding cables to move a load downward to compress against and stoprotation of the brake disk and drive shaft and to move down on the rampwhen the motor is winding the cables to move the load upward to allowrotation of the brake disk and drive shaft.

Some embodiments of the present invention include a fleet pivot arm,comprising: a U-shaped arm pivotably attachable to an end of a tubeabove a drive mechanism in a lift system; the arm having an upper blockadjacent the tube and a lower block adjacent the drive mechanism, thelower block pivotable in a direction substantially perpendicular to alongitudinal axis of the tube, wherein when the arm pivots, a pluralityof cables attached to a drum are routed along a desired fleet angle asthe cables are unwound from and wound onto the drum.

Some such embodiments of the fleet pivot arm can further comprise aroller on an inside of the fleet pivot arm adjacent the lower block andconfigured to roll against a pivot plate attached to a drive mechanismhousing as the fleet pivot arm pivots.

Some embodiments of the present invention include a lift system loadsensor, comprising: a first portion connected to a drive mechanismhaving a drum adapted to wind and unwind a plurality of cables about thedrum to raise and lower an article attached to the cables; and a secondportion connected to a drive mechanism housing, wherein each portion isadapted to be pulled against the other, thereby sensing changes in aload force on the article attempting to pull the drive mechanism awayfrom the drive mechanism housing, and wherein the load sensor is adaptedto adjust movement of the article when changes in the load force aresensed.

Some such embodiments of the lift system load sensor can furthercomprise: a set of slide rails attached between the drive mechanismhousing and a drive mechanism operably connected to the drum; and a loadsensor slide plate slidably mounted on the slide rails, wherein the loadsensor is operably attached to the load sensor slide plate, and whereinan increased load force on the article causes the slide plate to bepulled away from the drive mechanism housing, and the first and secondportions of the load sensor to be pulled against each other.

Some embodiments of the present invention include a method, comprising:providing a lift system comprising (a) a substantially rectangular tubeconnectable to an overhead structure, (b) a drive mechanism connectedexternally on one end of the tube, (c) a funnel-shaped drum operablyconnected to the drive mechanism, (d) a plurality of loft blocksconnected to the tube internally; routing a plurality of cables eachattached on one end to the drum through a generally horizontal path oftravel from the drum to one of the loft blocks, and then through agenerally vertical path of travel downward from the loft block;attaching an opposite end of each cable to an article; winding thecables about the drum to raise the article; and unwinding the cablesfrom the drum to lower the article.

In some such embodiments of the method, the drum can further comprise:an apex having a first diameter and a base having a second diameterlarger than the first diameter; a constant diameter portion having thefirst diameter and extending from the apex; a gradually increasingdiameter portion extending from the constant diameter portion to thebase; a plurality of discrete circumferential channels in the constantdiameter portion, each channel adapted to route and maintain one of thecables in a predetermined position about the drum; and a first one ofthe channels adjacent the gradually increasing diameter portionextending in a circumferential pattern about the gradually increasingdiameter portion; and the method can further comprise: winding a firstone of the cables in the first channel about the constant diameterportion and the gradually increasing diameter portion to the base,whereby notches are formed between adjacent coils of the first cable;winding a second cable in a second channel adjacent the first channeland into succeeding notches in the coils of the first cable; and windingsucceeding cables in succeeding adjacent channels in the constantdiameter portion and into succeeding adjacent notches in coils of anadjacent wound cable.

Some such embodiments of the method can further comprise winding each ofthe cables about the drum substantially simultaneously.

Some such embodiments of the method can further comprise: routing eachof the cables through a guide hole in a guide block of a cable guideassembly that is operably connected to the drum; and moving the guideblock at substantially the same angle as the drum to guide and maintainthe cables at the same fleet angle along the route to and from the loftblocks as the angle at which the cables are wound on the drum.

Some embodiments of the present invention include a method, comprising:connecting one end of at least one of a plurality of wires to an inputsource and the opposite end of the at least one of the wires to anoutput object movable with an article in a lift system; containing theplurality of wires in a wire containment cable; connecting a tray alongat least a portion of a length of a substantially rectangular tubeconnectable to an overhead structure, the tray having dimensions forcontaining the wire containment cable; moving the wire containment cablebetween a first, substantially vertical position when the article isfully lowered and a second, substantially horizontal position in thetray when the article is fully raised.

Some such embodiments of the method can further comprise positioning thewire containment cable in a single layer in the tray when the article isfully raised.

In some such embodiments of the method, the tray is connected to a topof the article.

Some such embodiments of the method can further comprise: attaching arotatable first roller to one end of the tray; attaching a movablesecond roller to the tray that is movable a predetermined distance alonga length of the tray as the article is moved; attaching the wirecontainment cable to the second roller and to a wire cable lift cablecomprising one of the plurality of cables; and guiding the wirecontainment cable by the second roller about a surface of the firstroller between the first and second positions.

Some such embodiments of the method can further comprise: a wire cableloft block located near an end of the tube opposite a drive mechanism,the method further comprising routing the wire cable lift cable from thedrive mechanism to and around the wire cable loft block and back in theopposite direction to the second and first rollers.

Some embodiments of the present invention include a method, comprising:providing a plurality of lengthwise portions of a substantiallyrectangular tube adapted for raising and lowering an article; connectingat least two of the plurality of tube portions to an overhead structure;abutting the at least two tube portions end to end; fastening togetherthe abutting ends of the tube portions using a splicing clamp comprisingan upper plate and a lower plate.

Some embodiments of the present invention include a method, comprising:providing a beam clamp tube receiver comprising a pair of opposing hooksand at least two opposing inserts movable vertically and spreadableinside each hook; tightening together the pair of hooks securely ontoopposite sides of an overhead structure; inserting a substantiallyrectangular tube adapted for raising and lowering an article into thebeam clamp tube receiver; and locking the tube in the beam clamp tubereceiver.

Some such embodiments of the method can further comprise sliding thetube in the beam clamp tube receiver in a direction perpendicular to theoverhead structure to which the beam clamp tube receiver is attached.

Some embodiments of the present invention include a method, comprising:providing a drum having a constant diameter portion; winding andunwinding a plurality of cables about the drum to raise and lower anarticle attached to the cables; maintaining the cables in position aboutthe constant diameter portion of the drum with a cable keeper comprisingan arm extending across the constant diameter portion along an axis ofthe cables and biased against the drum.

Some such embodiments of the method can further comprise guiding thecable keeper arm across the constant diameter portion of the drum at thesame rate as the cables wind onto and unwind from the drum.

Some such embodiments of the method can further comprise: monitoringtension on each of the cables with a slack line detector comprising aslack line sensor arm biased against each of the cables and movable inresponse to a loss of tension on the cables; signaling a cable controlwith a switch responsive to movement of the sensor arm; and adjustingmovement of the cables in response to a loss of tension on the cables.

Some embodiments of the present invention include a method, comprising:routing a cable in a lift system about a loft block and through agenerally vertical path of travel downward; routing the cable from theloft block vertically into a first cable guide having a 90 degree anglecable path, out of the first cable guide in a first horizontal directioninto one end of a second cable guide having a 180 degree angle cablepath, and out of the second cable guide in a second, opposite horizontaldirection to the cable guide; attaching the cable to an article to beraised and lowered; adjusting a horizontal adjustment mechanismpositioned between the first and second cable guides to change a lengthof the cable between the loft block and the article.

Some embodiments of the present invention include a method, comprising:providing a brake disk attached to a drive shaft operably connected to amotor and rotatingly positioned between a moveable brake pad moveabletoward a fixed brake pad; moving the moveable brake pad away from a rampto allow rotation of the brake disk and drive shaft so that the motorcan wind cables to move a load upward; and compressing the moveablebrake pad against the ramp to stop rotation of the brake disk and driveshaft when the motor is unwinding cables to move a load downward.

Some such embodiments of the method can further comprise: providing apivotable brake release arm adjacent the ramp; and gradually releasingthe brake disk after stopping rotation of the brake disk and drive shaftby tilting the drive shaft and the motor downward to actuate the brakerelease arm.

Some embodiments of the present invention include a method, comprising:providing a lift system comprising (a) a substantially rectangular tube,(b) a drive mechanism connected below one end of the tube, (c) afunnel-shaped drum operably connected to the drive mechanism, and (d) afleet pivot arm pivotably attached to an end of the tube above the drivemechanism and having at least one block; routing a plurality of cablesattached on one end to the drum through the at least one block; andpivoting the fleet pivot arm in a direction substantially perpendicularto a longitudinal axis of the tube as the cables are unwound from andwound onto the drum, thereby guiding the cables along a desired fleetangle.

Some embodiments of the present invention include a method, comprising:providing a lift system load sensor comprising a first portion connectedto a drum adapted to wind and unwind a plurality of cables about thedrum to raise and lower an article attached to the cables, and a secondportion connected to a substantially rectangular tube connectable to anoverhead structure, each portion of the load sensor adapted to be pulledagainst the other; sensing the load sensor portions pulling against eachother due to changes in a load force on the article; and adjustingmovement of the article in response to the sensed changes.

Features of lift assembly systems and methods of the present inventionmay be accomplished singularly, or in combination, in one or more of theembodiments of the present invention. Although particular embodimentshave been described, it should be recognized that these embodiments aremerely illustrative of the principles of the present invention. Those ofordinary skill in the art will appreciate that lift systems and methodof the present invention may be constructed and implemented in otherways and embodiments. Accordingly, the description herein should not beread as limiting the present invention, as other embodiments also fallwithin the scope of the present invention.

1-12. (canceled)
 13. A lift system configured to move an articlerelative to a beam, the lift system comprising: a drum rotatable aboutan axis; an elongate member coupled to the drum, the elongate memberconfigured to be coupled to the article; a beam clamp configured to befixed to the beam; a tube coupled to the beam clamp; and a loft blockcoupled to the tube and configured to guide the elongate member to raisethe article when the drum rotates about the axis in a first directionand to lower the article when the drum rotates about the axis in asecond direction, wherein one of the beam clamp and the tube includes aslot, and wherein the other one of the beam clamp and the tube includesa protrusion positioned within the slot such that the tube is coupled tothe beam clamp.
 14. The lift system of claim 13, wherein clamps arepositioned within the slot for the clamps to engage the protrusion. 15.The lift system of claim 14, wherein the protrusion includes a flangeengageable with the clamps for the tube to hang from the beam clamp. 16.The lift system of claim 15, wherein the flange is inserted between theclamps in a first direction, and wherein the clamps move relative to thebeam clamp in response to the flange being inserted between the clamps.17. The lift system of claim 16, wherein the protrusion and the clampsmove in a second direction opposite the first direction for the tube tohang from the beam clamp.
 18. The lift system of claim 17, wherein theslot is defined by a plurality of walls, wherein each of the pluralityof walls includes a tapered tip, and wherein the tapered tips restrictmovement of the clamps in the second direction.
 19. The lift system ofclaim 13, wherein the tube includes the protrusion, and wherein the beamclamp includes the slot.
 20. The lift system of claim 13, wherein a snapconnection is provided between the protrusion and the slot to secure thetube to the beam clamp.
 21. The lift system of claim 13, wherein theprotrusion is fixed to the one of the beam clamp and the tube.
 22. Thelift system of claim 13, wherein the loft block is a first loft block ofa plurality of loft blocks, and wherein the plurality of loft blocks arecoupled to the tube along a length of the tube.
 23. The lift system ofclaim 13, wherein the drum is coupled to the tube.
 24. The lift systemof claim 13, wherein the tube includes a channel having a longitudinalaxis extending between opposite ends of the tube, wherein the channelreceives a portion of the loft block to couple the loft block to thetube, and wherein the loft block is selectively lockable in a pluralityof positions along the longitudinal axis of the channel.
 25. A liftsystem configured to move an article relative to a beam, the lift systemcomprising: a drum rotatable about an axis; an elongate member coupledto the drum, the elongate member also configured to be coupled to thearticle; a tube configured to be attached to the beam, the tube having alongitudinal axis between opposing ends of the tube; and a loft blockcoupled to the tube and moveable along the longitudinal axis of thetube, the loft block lockable in a plurality of positions relative tothe tube along the longitudinal axis, the loft block configured to guidethe elongate member to raise the article when the drum rotates about theaxis in a first direction and to lower the article when the drum rotatesabout the axis in a second direction.
 26. The lift system of claim 25,wherein the loft block is wedged in a channel of the tube to lock theloft block relative to the tube.
 27. The lift system of claim 25,wherein the loft block is configured to move upwardly toward the beam toallow movement of the loft block relative to the tube, and wherein theloft block is configured to move downwardly away from the beam to securethe loft block to the tube.
 28. The lift system of claim 25, wherein thetube includes a channel defined by a plurality of walls of the tube,wherein the plurality of walls each include a rail adjacent an openingof the channel, and wherein the loft block slides along the rails toposition the loft block in the plurality of positions relative to thetube.
 29. The lift system of claim 28, wherein the loft block includes alocking mechanism, and wherein the locking mechanism is operable to lockthe loft block relative to the tube in response to the locking mechanismbeing actuated.
 30. The lift system of claim 25, further comprising abeam clamp configured to be fixed to the beam, wherein the tube iscoupled to the beam clamp.
 31. The lift system of claim 30, wherein oneof the beam clamp and the tube includes a plurality of walls defining aslot, and wherein the other one of the beam clamp and the tube includesa protrusion positioned within the slot such that the tube is coupled tothe beam clamp.
 32. The lift system of claim 31, wherein a snapconnection is provided between the protrusion and the slot to secure thetube to the beam clamp.